An elaboration on No Plans, No Prototype, No Backup.
In engineering terminology, a "black box" is a device with one or more inputs (cake ingredients, an excerpt of text in Mandarin, iron ore), one or more outputs (cake, the same text translated into Frisian, a battle golem), and internal processes that are either:
unknown and/or unknowable.
Such technology falls into the hands of some organization, usually the military or a commercial business. The original creator is dead (or is an alien or from a long-dead civilization or otherwise can't be reached), but said technology is really convenient. The organization's analysts went over the thing, and while most of it makes sense, there are these elements, either program or device, that they cannot comprehend at all. Removing them causes the entire thing to simply not function (or triggers a moreactiveresponse). The organization may be able to reverse-engineer copies, or lesser versions, but they don't understand how it actually works.
So, since the financial bottom line or military advantage is so important, they go along with it anyways.
....yes, of course, the technology has a bizarre effect that nobody could have predicted - you really need to keep track of those inputs and outputs! Usually it's in the form of acquiring sentience or a bizarre weapon, or only being able to be used by people of the show's target demographic. (It's common in Humongous Mecha series.)
This is surprisingly common in Real Life, particularly in programming, where the programmer is the only one who really understands how what they've built works (and sometimes, not even themnote
For an analogy, solve a complex math problem without writing down anything but formulas and equations, and try making sense of it a couple weeks later.
In .hack// CCCorp treats The World as the game it appears to be, but those who can find the so-called "Creator's Rooms" can discern some of the original designer's true intent.
And the game keeps sucking up player's, programmer's, and administrator's minds; even after they've rewritten it twice. Even so, that's much safer than the alpha version. Many were terrified of even playtesting it, particularly after its creator died playtesting it. Actually, Harald didn't die, but his mind was absorbed into the program completely.
The core code of The World is explicitly referred to as a "Black Box" in several of the novels.
There are also occasions where the game circumvents or thwarts the administrators' attempts to fix issues, such as banning certain players, as well as spawn vagrant AIs.
The development of the Evangelions in Neon Genesis Evangelion is very much along the lines of this trope, although the source of the Black Box is not earthly.
The S2 engine is a particularly fitting example. American attempts to reverse engineer the device result in a massive disaster - the test engine vanishes, along with the entire research facility and all other objects in a 50-mile radius.
Also, the Lance of Longinus. We have no idea what it is, but dang does it tear Angels up. The replicas are decidedly less effective.
The plants in Trigun can do pretty much anything depending on how you power them, but nobody's really sure how they run anymore. (The manga actually calls them "humanity's ultimate black box".)
The flying machines in Simoun have two black boxes: the "Helical motor" (according to the sub) and the "Simoun Gem". Trying to find out how these things work apparently drives you mad for a little while.
Black Boxes are a dime a dozen in The Big O, ranging from nigh-indestructible giant robots to androids to underground tunnel networks. The last episode reveals that the plane of existence is one big Black Box. The only comprehensible objects in the series are tomatoes, and those are a type of mysterious lost technology.
It's all but stated outright that the Otome were based on the Hime, the "natural" magical girls from Mai Hime. So it's a Black Box replicating magic. Its a damn miracle it works at all.
The Clow Cards in the first arc of Cardcaptor Sakura. The cards are sentient, though astonishingly specialized*
Only some. Sweet, Song, Flower, and similar are almost pointlessly specific, but the rest are either multi-function in and of themselves (the elemental ones), straight-up buffs (Dash, Fly, Fight, etc.), or hugely useful tools in many circumstances (Sword, Mirror, Illusion, Loop, etc.).
, and their creator is dead but returns anyway in the form of his reincarnation in the second arc..
Zoids, anyone? The Ultimate X zoids are shown to have a "black box" that other zoids do not.
GaoGaiGar mentions this. In one flashback, they actually discuss a strange interface on Galeon, an alien mecha lion, and refer to it as a Black Box. Once they figure out how to activate it, it contains designs for half the Applied Phlebotinum in the show.
In the Nausicaa manga, the Crypts of Shuwa are full of Black Boxes—most notably the God Warrior. More mundanely, nobody has the technology to build new airship engines any more, so when an airship is downed, there's a scramble to salvage the irreplaceable engines.
In The Second Raid it's mentioned that the Arbelest is optimised for the first person who used it (Sousuke) and as the designer died since then that means it can't be reset for another user. As Sousuke hates the unreliability of the weapon and is also undergoing a Heroic BSOD this causes major problems.
The FMP manga Arbalest won't work for anyone other than Sousuke because if anyone else tries to pilot it the AI just constantly asks for Sousuke, and no matter how many times the reset or reprogram the thing it still will only work for Sousuke.
Full Metal Panic Fumoffu used this to humorous effect with the Bonta-kun class Powered Armor — it has a voice filter that renders all spoken speech as "Fumoffu!" to anyone listening. It causes the armor to shut down if disabled, and no one — not even Sousuke, who designed the thing — knows why.
Humans don't seem to figure out how to replicate Ganmen during the timeskip of Tengen Toppa Gurren Lagann. The Guraparls that form the backbone of the Earth military were reverse-engineered from Gurren Lagann, but they don't seem to have figured out much about Spiral energy or how to reverse-engineer the "generator" that lets a Ganmen use it. This means that forces initially superior to the Ganmen they replaced wind up looking like anemic kittens once the hot blood Goes To 11... Million...Though it also has to do with the ganmen's purpose of fighting anti-spirals.
This is explicitly because Rossiu believes the Ganmen to be inferior and a reminder of Lord Genome's reign and so he had them destroyed rather than any lack of ability on the part of the humans.
The Reveal of Outlaw Star. The eponymous Cool Ship and Melfina were created based on the unknown data (the black box) that Gwen Khan could not translate from an advanced ancient civilization which is implied to have created all of the ancient ruins of the galaxy. Only Melfina can open the door to the Galatic Leyline itself, and grant the people that go there their ultimate desire.
For a while the Caster Gun employed by main character Gene Starwind was a black box of lost knowledge. Caster guns are essentially antique pistols that fire unique shells with a wide variety of effects that can even counteract the magical attacks of Tao Masters. Nobody knows whether they are lost technology or, as later confirmed, magic that has been encapsulated within the shells.
The GN drives in Gundam00. GN Drive technology can be mass produced in months (reversed engineered by The Federation from the GN-X drive model), but true GN Drives, the ones which emit green "pure" particles used by Celestial Being's Gundams, are equipped with a "Topological Defect" Blanket, which can only be manufactured around Jupiter with a total production time of six years. Somehow harnessing the power of topological defects (a mathematical solution involving differential equations) allows the drive to funnel energy back into itself, allowing for unlimited operation time.
Additionally, Celestial Being's true GN Drives have a literal black box which no-one could figure out, which turns out to contain the data for the Gundams' Trans-Am Function and the Twin-Drive System.
Darker than Black has alien technology and powers coming from the "Gate" — among other things, tech that allows for Laser-Guided Amnesia, glowing flowers whose seeds halt the development of Contractor powers, and crystalline plants whose pollen make bees produce an intoxicating drug. Possibly inspired by Roadside Picnic (see below) — at least, it can be interpreted as a homage to and discussion of its setup.
This is a main plot point in Robotech: The Shadow Chronicles. The Haydonites provide humans with shadow technology which greatly aids them in fighting Invid. But the technological information supplied by Haydonites is incomplete, so even though the shadow devices were built by humans themselves, they still have flaws which Haydonites exploit when they attack humans.
In the American release of Voltron (which combined the separate series Go Lion and Dairugger XV), it's established that the Vehicle Voltron was built as an imitation of the original Lion Voltron built by the late King Alfor of Arus. Since the original Voltron is semi-mystical in nature and the magic was not copyable, the duplicate can only stay unified in giant robot form for five minutes at a time.
Used in Mahoromatic. Mahoro was built using incompletely-understood Imported Alien Phlebotinum, including the power source. Which leads to the Death Clock - as the power source cannot be refueled or recharged by Earthly technology. It CAN be recharged by SAINT - they just don't get around to doing it in time, focusing on fixing the horribly-botched job on Minawa first.
A scientist in Yozakura Quartet equates the workings of youkai and supernatural powers to Black Box technology. He makes the comparison that just as we don't understand how magic works, most people don't understand how a computer turns on apart from pushing the "on" button.
In Knights Of Sidonia the Kabizashi blades, which are the only weapons that can kill Gauna. No one knows for sure how they work, and no one knows how to make more of them.
The first three T.H.U.N.D.E.R. Agents were all recipients of black boxes. As their origin shows, their devices were found amid the rubble of the lab of a famous inventor, who had been killed by minions of the Warlord. The Warlord's mooks had looted the place, but missed a few items. Several early stories were about the agents discovering drawbacks to their new powers.
Captain America's shield is essentially a Black Box in design; made of an unknown alloy of Vibranium, other metals and a mysterious bonding agent- which the creator doesn't know about, having fallen asleep during its production- which results in a shield that has properties unlike anything else in existence. Some say that agent was American Rightousness (as opposed to American self-righteousness), explaining why it seems to act as almost an Empathic Weapon to Cap.
In Ultimate Marvel and the Marvel Cinematic Universe, the serum itself was quickly replicated, but an army of Captain Americas is still impossible because the recipient is the key factor; In Ultimate, it only works on subjects with superhuman willpower, keeping the successes at a minimum. In the MCU, it grants Personality Powers, meaning unless the government is willing to stick needles in a card-carrying saint(who would thus never perform deniable operations), all they would get is more Red Skulls.
One attempt to recreate the success of Captain America failed because the serum is only part of the process. Without the "Vita-Ray" treatment, the recipient's body couldn't safely take in the serum.
The night before Steve Rogers received the treatment, a General who disapproved of Steve Rogers' perceived weakness as a candidate had a more aggressive soldier treated with only the serum, not the Vita-rays. The treatment drove the subject insane, and after being taken down he was put into cold storage. He was woken up in the "present" day and had his insanity cured by A.I.M. Stronger, Faster, and far more aggressive than Captain America, he was brainwashed into believing Steve Rogers had stolen his mantle, and tried to get revenge on Cap as Protocide, .
Sonic the Hedgehog's NICOLE. It came down from the SKY, and not even their technical expert Rotor knows how it works. He did use the system to beef up his firewalls, to Eggman's extreme annoyance:
Eggman: "I HATE that Rotor! I hack and I hack, and I hack, and do I find anything? Do I get past his firewalls? NO! Not only is his defense system too good...
The Firewall: *is doing a raspberry at him*
Eggman: It's downright RUDE!
The guidance system abroad the Russian communication satellite in Space Cowboys is so archaic that no one except the original creator understands it.
Something of a subversion, since the technology isn't too advanced or hidden, it is simply not known to the current generation of astronauts due to its extreme obsolescence. "It's pre-microprocessor! It's pre-EVERYTHING!"
In Captain America: The First Avenger, when the Red Skull finds the glowing blue Tesseract (implied to be the all-powerful cosmic cube of marvel comics) he uses it as an energy source for his tanks and weapons. Until his supposed death when the cube sustained damage from Captain America's shield and began to warp reality itself, he only saw it as an unlimited power source. Ditto for the scientists on the American side, who attempted to harvest the minuscule yet overwhelming bits of energy powering the guns (blasting a hole in one of the research facilities when they tried to discover its properties). What will happen to the cube now that it is in U.S. hands after Red Skull's death, only time (and the Avengers movie) will tell.
It only got more Black Box-y in The Avengers, when the Tesseract starts opening wormholes to other areas in the galaxy on its own, because Loki has figured out how to operate it remotely. The government can't even stop him from doing this, despite years of study.
Tony Stark's ability to miniaturize the arc reactor is what drives Stane mad in the latter half of Ironman, since Tony didn't exactly leave any blueprints of it in the Terrorist's base and none of Stane's Scientists can duplicate it (leading to his Memetic line about Tony building stuff in a cave with scraps). In Iron Man 2 the fact that the Ironman suit and miniature Arc reactor apparently not being Black Box tech is what kicks off most of the plot.
In The Thran, the whole Thran Empire relies on powerstones as their source of energy, but even the engineers who work on them don't exactly know how they work.
The Strugatsky brothers' Roadside Picnic, as well as The Game of the Movie S.T.A.L.K.E.R (but oddly enough, not the movie) have a Danger Zone full of Black Box alien artifacts as the catalyst for the plot.
In Discworld the Devices discovered by dwarfs are ancient Black Boxes with assorted functions, including power sources and recording devices. The magical supercomputer Hex is also a Black Box; it's added so many peripheral devices to itself that even its original designer, Ponder Stibbons, is no longer sure exactly how it works.
A particularly good example is Hex's teddy bear- a simple cuddly toy, yet when taken away from Hex, Hex refuses to operate.
With the error message +++Mine! Wahhhhhhh!+++
In His Dark Materials, the subtle knife certainly fits the bill. It is an ancient weapon that can cut through anything, including the fabric between dimensions. However, it has the unfortunate effect of creating a soul-eating monster every time it is used, and eventually weakening the equilibrium of the universe. The alethiometer also qualifies, though it has no negative effects.
The Legacy Of The Aldenata series features a number of examples of the Black Box. The alien Posleen (or "people of the ships" in their language) are similar to the Covenant in Halo in that they use technology they understand poorly if at all. A perfect example of this is one of their commanders staring in confusion at a computer helpfully informing him "Incoming ballistic projectiles. Impact in 10 seconds. Five.... etc" The views of their society in the initial books of the series are vague for the most part but imply that they only really use the systems that kill things or are almost entirely automated. A literal black box used by the humans in the same series appears in the form of the AID which is a black memory plastic box about the size of a pack of cigarettes with an extremely potent AI embedded in it. They act as a Universal Translator as well, but are provided by another species and the humans haven't a clue how they really work or how to make them. This turns out to be a serious problem for a number of reasons
There is also the small black box from his and Travis S. Taylor's Into The Looking Glass books, a device about the size of a pack of cards does "interesting" things with spacetime. It was given to them by the friendly aliens at the end of the first book, who had found it on some other planet and had no idea what it was for. Although they did warn that one should NOT apply a "significant voltage" to it. Hooking up a double-A battery leaves a 10-mile crater. A car battery destroys the (deliberately uninhabited and unimportant) planet. Three-phase current erases the solar system. They eventually figure out how to turn it into a warp drive and use it to power the ASS Vorpal Blade. Turns out hooking it up to a car battery was using it wrong.
In Robert Jordan's The Wheel of Time there are the ter'angreal (magical items), the secret of whose making has been lost for three thousand years. The Aes Sedai keep plenty of ter'angreal around for use as black boxes without understanding how they work, and many more items where they don't even know what they do.
Being subverted in the more recent books as Elayne and Egwene begin discovering how to make them again.
In Frederik Pohl's Heechee Saga, the entire plot of the first few books revolves around highly advanced alien space ships, though they do eventually manage to decipher the instruction manuals.
One big one is that after you set the targeting crystal, that no human understands, which glows various colours and auto-locks by AI, anyone who has changed those settings after launch has disappeared.
The hero eventually finds out why.
Parodied in The Galaxy Game (by Phil Janes) where a scientist trying to master FTL for a trip to the stars finds three small boxes each printed with the words "Inertialess Device" in his kitchen cupboard one day. We later find out they were put there by bored Energy Beings who pit civilisations against each other for sport.
In David Brin's Uplift series, all of the alien species in Galactic civilization are happy to use technology they don't understand and can't repair, so long as it comes with the blessing of the Great Library passed down by their revered ancestors and somebody, somewhere, knows how to repair or replace it. The exception is Humanity, who know darn well that relying on such tech will make them economically dependent on other species. They try to use their own (comparatively very primitive) tech while struggling to learn how alien devices work. Occasionally, Humans even benefit from Rock Beats Laser. But even Earthclan has to rely on Black Box technology for certain things — i.e. reality shields, psi shields, hyperspace, and the Library itself.
This is a major feature in Alastair Reynolds' Revelation Space novels. Everyone uses a certain kind of stardrive, but only the makers know how they work, and fiddling leads to an enormous explosion. The most powerful weapons are barely-understood gifts from Sufficiently Advanced Aliensor future humans who will sent the blueprints back in time.
Judging by one character's vauge discription of the internal conditions in a stardrive in "Weather", the Conjoiners kept the stardrive technoloy Black Box so that the 'retarded' (everyone else) wouldn't try and weaponise it. And also because of the whole disembodied-brain thing...
The O/BEC processors in Blind Lake. Created by accident due to the use of self-rewriting code, not even the scientists who operate them are quite certain how they do what they do. There are only two in existence; all attempts to make a third by replicating the conditions that lead to the first two have failed.
This exact phrase is used to describe the Highway in William Gibson's short story "Hinterlands". Astronauts go in and come out, sometimes bringing back pieces of alien civilisation with them. The "jump" only happens when the astronaut is alone and they all, invariably, come back either dead or catatonic. Sometimes the jump doesn't happen at all...
It's a particularly interesting case, as Galt realized that the unbelievable stupidity of Starnes heirs were the symptoms of a cultural decline. He could thus safely walk off and leave the prototype and the plansright there in the lab without fear that they would be stolen, as no mind capable of understanding how valuable they were, let alone making use of them, would ever work there again. A notable subversion of Low Culture, High Tech.
Colson Whitehead's The Intuitionist. The main MacGuffin in the story is known as the Black Box.
In Robert A Heinlein's universe there is the Shipstone; a battery that comes in sizes from a lifetime miniature system for a flashlight, to a large battery that can power a house, to a possibly colossal one that powers space ships. The black box-ness of it comes because the inventor never patented it, since that would require that he publish the schematics. he just started a company and started manufacturing them under lots of secrecy. Attempts at dismantling and reverse engineering a shipstone usually resulted in a big kaboom.
The Robert A Heinlein/Spider Robinson novel Variable Star has a living black box in the form of Relativists. These are men and women who can coax a ship's engines to accelerate to relativistic speed apparently by Comtemplating Their Navels. The Relativists think up a number of poetic descriptions of what they do all day to keep the engines going, but in the end they admit that even they aren't really sure how they're doing it.
The starship Heart of Gold features the infinite improbability drive that enables improbability manipulation up to a point where the ship exists everywhere at once and can drop out anywhere instantly - universe wide teleportation. The hitch is that nobody knows how the improbability drive really works, some smartass janitor just figured out one day that all he needed to know was how improbable it was for that drive to come into existance and voila, instantBlack Box.
The starship Bistromath works on a similar principle. In restaurants math works differently than anywhere else in the universe. This is why you can never correctly guess what the bill will be, what a proper tip is, how much each person at the table should owe, etc. Nobody knows why this is, or how it works, but that doesn't stop them from building a spaceship modeled on a small Italian Bistro to take advantage of this fact and break several laws of physics.
The Belt of Deltora from Emily Rodda's Deltora Quest is technically a Black Box, with the belt part itself the box and the gems the internal mechanisms. It can be assumed that no one knows exactly how it works; indeed, how it works is irrelevant. All anyone knows is that the Belt is "greater than the sum of its parts" and removing one of the pieces (i.e., one of the gems) would stop it functioning.
In Animorphs, the kids are given the power to morph by touching the Blue Box by the alien Elfangor right before he is eaten alive by Visser Three. Later, David shows up with the same blue box and it is used to give him morphing power even though no one present has any idea how the technology works. This happens later again when the Auxiliary Animorphs are created, and yet AGAIN when the Yeerks steal the blue box and use the morphing power to create their own solidiers with the morphing ability.
In Ian Irvine's Well of Echoes series, the clankers draw energy from nodes. No-one knows why it works, but their are some illegal books that speculate on these topics.
This becomes a major problem when nodes start to fail, because the humans depend upon clankers to fend off the lyrinx that have been killing the human race.
The Machine Of Death is a device that takes a person's blood sample and predicts how that person will die. It's cheap to use and possible to duplicate, but no one knows how it works.
Redshirts has the Box, a microwaved shaped device that if given a sample of any xenobiological problem, will go 'ding' and provide the solution when dramatically appropriate. Truly unusual due to the fact that even the writer for the show doesn't know where it came from, since it never appears in any scene that is filmed. It just appears out of nowhere so that all the miraculous cures needed in the show are possible.
In Vernor Vinge's Rainbows End, pretty much all engineering is done by putting together modular black boxes whose contents are unknown, except to the companies that manufacture them. This is done to protect copyrights and trade secrets. Plus, it's supposed to make things simpler. At one point, Robert Gu gets frustrated, and tries to open a black box under the hood of a car, using a cutting laser. The result is an explosion.
Live Action TV
Stargate SG-1 often adapts lesser versions of the technology the crew encounters from other planets. "It doesn't quite work like the original" is commonly stated. However, they're far more aware than most Black Box users of the potential for unexpected side effects.
In fact, nearly every piece of technology they pick up is mentioned to be sent off to Area 51, either in the episode where it's introduced, or when they decide to use it again. This leads to situations that look like Forgotten Phlebotinum, until two or three years down the line where the device pops up again. Except for anything that comes with a trigger (Zat guns, anyone?) which is usually put into active service immediately. Which should come as a surprise to nobody, since military usage (including stuff that makes an Earth-Shattering Kaboom) is usually the first application mankind can think off for any given tech. Naquadria bombs, anyone?
Which makes sense in a way, as acquiring weapons to defend Earth is the SGC's first mission.
There are few ideas that are missing however. So they can take apart staff weapons but can't build them or speed up rate of fire but could find them by the buttload after a firefight right? Well, seeing as how that whole unlimited ammo for machine guns thing would be very useful in their fighters, why didn't they strap six or seven of the firing portion onto a rotating contraption and make an impromptu gatling weapon and mount one of those?
It was mentioned in show, that kinetic weapons make better infantry weapons because staff weapons are self-cauterizing and less accurate. As for space weapons, they probably never actually captured a ship class staff weapon. The infantry ones they have are much less powerful the the F-302 railguns.
While never utilized in the show, that idea is one of the first uses Humanity finds for all the extra Staff Weapons in the Fan-Fic series 'XSGCOM', among other things...
This also extends to the spinoff/sequels Stargate Atlantis and Stargate Universe, where the protagonists uncover a dearth of Ancient and alien technology. Though they know how to operate the Ancient technology they find (most of the time), they don't know their exact inner workings.
The Goa'uld, on the other hand, make very little effort to study the Ancient technology they use. They've based their empire on things like the Stargates and ring transporters, but they really have no idea how any of it works.
Most Goa'uld are like this, but a few tech-savvy ones do try to make new tech. Clear examples are Anubis (although he's just reverse-engineering Ancient tech) and Ba'al (who understands the programming used by the gate system on a deep level and has messed around with gravity manipulation). In fact, it's the bigshot System Lords who usually don't bother with the tech stuff, but there are many underling Goa'uld who serve as their technical specialists. It's not that they don't know how Ancient-derived tech works, they just don't see the point in trying to improve it if it will upset the status quo.
In the re-imagined Battlestar Galactica, it's eventually revealed after the destruction of the Resurrection Hub that the "Significant Seven" Cylons don't understand how the resurrection process they use actually works, and so they can't reconstruct it after it's gone. Only the Final Five have the knowledge necessary to recreate the technology, since they designed it in the first place.
The positronic brain that makes Data a Ridiculously Human Robot serves as his black box in Star Trek: The Next Generation. While Starfleet has a pretty good idea of how the rest of his body works, the technology that actually makes him sentient is a complete mystery to them, especially since the genius inventor who built him is dead. They're understandably reluctant to take Data apart to figure it out, since they don't know if they'd be able to put him back together afterwards, and after a particularly overzealous researcher took the issue to court, Data gained the legal right to refuse such a dismantling anyway. His own attempt to replicate the technology seemed to succeed when he built a "daughter", Lal, but her positronic brain became unstable and she only lived for a few weeks. Nobody's tried to build another one since.
Also, the risk of creating another Lore (Data's dangerously flawed older brother) highlights the risks of building anything less than a flawless brain on the first attempt.
The term non-Euclidean here is meant to be a hint of how complex and hard or impossible to understand this geometry is, rather than a strict description. According to one article, 4D geometry isn't Euclidean because there's an easy way for corners to mathematically become curves. We're familiar with geometry that works with respect to spheres, because trying to travel in a large enough square path will not result in getting to the original place. That's a standard example of non-Euclidean geometry. Imagine going to a realm where backtracking would also take you to a different place. Or travelling in distances that cannot be expressed only in real numbers, so imaginary numbers must also be used. See Alien Geometries.
Mathematicians most likely have theory that works with these geometries as well. They seem to like inventing things that can cause madness in more grounded in reality people. Fortunately, most of these are kept out of public view.
4D geometry can be Euclidean. Can be not. It's not a case of dimensions - Minkowski space(time) can be easily represented for 2D instead of 4D as in special relativity. Actually we are sure since special relativity has been <del>proved</del> <ins>not disproved</ins> that our space is not Euclidean. Set Theory did drive people insane.
"In the center of every ANIMa creche lies a scavenged piece of an alien's brain. It's possible that this is the only thing that an ANIMa requires to function, and that the rest of the machine is there to inspire more confidence on the part of the pilots." - Bliss Stage: Ignition Stage rulebook
In the Eberron campaign setting of the Dungeons & Dragons roleplaying game, black box magic was used to develop the warforged through schemas, which are essentially magical blueprints conveniently left behind by an ancient giant civilization. It turns out (in the Secrets of Xen'drik supplement) that it was an attempt by an ancient extradimensional race to escape to our world from the realm of dreams by creating artificial bodies, though this doesn't explain why modern warforged are fully sentient and appear to have souls.
Syrneth artifacts in the 7th Sea RPG setting are an intentional use of this trope. Syrneth technology doesn't just do whatever is convenient; the results of humans tinkering with it can have effects ranging from miraculous to horrendous, and sometimes no effect at all.
Syrneth artifacts also run the gamut in regards to the complexity of their function. The Pirate Nations sourcebook includes several that players can purchase. They include a completely functional cybernetic hand and a marble that, once tapped, will always roll back to the position it was last tapped, showcasing how bizarre some of the effects can be.
As a borderline Scavenger World, Warhammer 40000's Imperium of Man has some examples of this. A great deal of technological knowledge has been lost over the millennia, and as a result many of the devices lovingly-maintained by the rituals of the Adeptus Mechanicus are irreplaceable ancient relics. One example would be the Standard Template Construct systems, self-contained manufacturing programs that can produce anything from medicine to battle tanks to knives - they're some of the most valuable treasures in the galaxy, and the Imperium eagerly uses them whenever one is discovered, but nobody has any clue how they function and certainly isn't going to risk cracking one open to find out.
What the ST Cs actually are depends on the author, although they may just use the same name for different systems. The most common is that it was a massive database on how to build anything given basic tools and resources without any real mechanical or scientific skill, but the last working system was lost millenia before the founding of the Imperium. The print-outs of a few plans that remain are the most valuable things in the galaxy as a result.
A nonhuman example would be the Blackstone Fortresses of the Gothic Sector, a sextet of ancient space stations left behind by an extinct alien race. The AdMech were able to patch into the stations' power systems and hook up their own weapons and life-support, but nobody was sure of the things' function... until Abaddon the Despoiler showed up with some artifacts of his own and fully activated the Blackstone Fortresses, deploying guns that tore holes in space-time and could make suns go nova.
The Space Marines' implants cannot be duplicated since the source material needed to create more of them, the Primarchs, are dead, lost, fallen to Chaos, or are otherwise in no condition for harvesting. Even worse, the God Emperor of Mankind is the only person alive(ish) who knows how to create more Primarchs, and he's been trapped in living death for 10,000 years. If a Marine falls in battle, retrieving his implant is his comrades' top priority, since each lost implant means one less Space Marine ready to fight against the enemies of humanity.
To humans, Tau technology is this: they simply cannot fathom how their technology works without first placating the "machine spirits" (which may actually exist, Depending on the Writer) with incense and rituals. They don't get how ork stuff works either (for that matter, neither do the orks), though they just figure the orks shout and whack their machine spirits into submission.
Mad Science in Deadlands is a prominent example. A Mad Scientist may create fantastic devices that surpass anything "regular" science is able to produce, but it's impossible to mass-produce Mad Science gizmoes - they just don't work. Throughout the centuries, Mad Science gains or loses popularity, depending on the shifting popular opinion. Mad Science is partly magical, the ideas for it coming from Manitous, malevolent spirits serving the setting's Big Bads. It is part of a master plot to (eventually) bring about Ghost Rock bombs, nuclear weapons capable of warping or killing spirits of living things, and to transform the entire Earth into a terror-filled wasteland.
It also adds some serious Fridge Horror for anyone who is scientifically inclined. Imagine being a scientist or engineer (the most common people who become Geniuses), someone who dedicated their career to discovering the truth and pushing technology forward and creating something that can bend the laws of reality... but you can never show anyone, can never prove anything and you will never know how it works.
Subverted in Exalted. Many of the great and wondrous artifacts can be understood... it's just that most of the great designers would have been among the Solar Exalted, who were murdered and had their Exaltations sealed away so they couldn't reincarnate. It doesn't help that the Solars specifically designed many artifacts to only function for Solars... because they never imagined there would be a time when they weren't around.
In theory, any Celestial Exalt (or Terrestrial of sufficient age and experience) could bring themselves to understand the complex workings of Solar artifice. The problem is that reaching that level of excellence is much harder for non-Solars, they can't achieve nearly the same level of speed, and besides they've been a bitdistractedsince then.
Well, now that the Solar Exalted are back, they can begin reverse engineering all of the old First Age tech... as can their corrupted cousins, the AbyssalExalted and InfernalExalted, whose bosses have other ideas about what to do with all of that technology.
To a degree, Exaltations themselves are black boxes, to the point where the guy who made the Celestial-tier shards probably can't make any more*
partly because he's comatose and dying of robot-cancer
. The main alterations made have been the result of insane supergods launching curses fuelled by the power of their own deaths (the Great Curse), the random action of a zone of infinite probability (the breaking of the Lunar castes), flipping a switch that may have been there all along (Abyssals), and using an intact Solar shard as the battery pack for a web of Yozi Essence (Infernals). Alchemicals can only be made by demiurges channelling the Design of Autochthon and have no idea how to make more when not channelling. About the only Exalts it's easy to make are Dragon-Bloods, and that's because all you need is two other Dragon-Bloods, one male and one female.
Xenosaga: KOS-MOS is an android built by Kevin Winnicot, but when she goes berserk and murders hims she has to be rebuilt. Unfortunately, the only way Kevin's successors are capable of creating another KOS-MOS is to simply repair and (attempt to) reprogram the same prototype unit that killed him because he took the plans for her to his grave. As a result, the current KOS-MOS is treated like a faulty handgrenade which her development team is loathe to admit they have zero control over if push comes to shove. She's laden with black box parts and programs, each with unknown functions, which come online at seemingly random intervals (like her Gnosis-obliterating X-Buster ability), often to shocking effect. Series protagonist (and KOS-MOS co-creator) Shion is only able to figure most of them out enough to rebuild KOS-MOS a second time after gaining access to Kevin's original plans via a time paradox.
Also, a great deal of the series's technology is the product of one man, Joachim Mizrahi. After he died on Militia during the Federation's invasion, a great amount of effort has been poured into piecing his prototypes back together, as well as reassembling his codex of knowledge: the Y-Data. Efforts to recreate his work from scratch by his rival Dr. Sellers amount to impressive, but fatally flawed knock-offs.
Xenogears has Gears, the giant mecha of the game. Gears are obtained both through construction and excavation, but it's never elaborated to exactly what ratio most Gears are are comprised of irreproducible black boxes, copyable black boxes, and commonly understood technology. The primary Gear of the game, Weltall, is comprised almost entirely of black boxes, which, much like KOS-MOS, are stunningly powerful and come online at seemingly random intervals. According to the Perfect Works Book, most of the black boxes are either Ether amplifiers, or components used in its transformation between Weltall and Weltal-Id-. Eventually, Weltall is transformed into the titular Xenogears, becoming a 100% Organic Technology black box, in addition to being the most powerful Gear in the game.
In the Mega Man X game series, the sentient robot X is copied imperfectly, resulting in the Maverick uprisings.
The documentation for the original SNES game outright stated that there were some systems that Dr. Cain just didn't understand and therefore didn't reproduce. He even called them "Black Boxes". It's unknown if these parts were part of X's ethical training, or his various weapon systems (his ability is repeatedly described as "limitless", and no one understands why). Later games revealed that Zero has similar black boxes, mostly likely stolen by Wily.
But in the Mega Man Zero series, Ciel, as a young kid, manages to reproduce X perfectly. Unfortunately said perfect reproduction showed why Dr. Light had X put into ethic training sleep for at least 30 years.
Ciel's no slouch though; didn't she spend much of the series developing a revolutionary new energy source, one that would end shortages and bring about world peace? Yeah, you never saw Dr. Cain pulling something like THAT off.
And then you can't call it a perfect reproduction. Yes, it looked like X, it had an arm cannon, a variable weapons system (though he only used three moves), and a set of armor... but it's much weaker than X in many ways and in fact is quite comparable with the clone body Zero is in.
A rare example where the black box is in the alien's hands is in the Halo universe, where all of the super powerful technology used by the Covenant are just leftovers of another alien race called the Forerunners. Instead of even trying to discover the means of its operation, they take them to have divine powers and remember the Forerunners as gods. For this reason it has been established that they do not even use the technology very efficiently. By contrast, human attempts to analyse captured Covenant technology, as demonstrated in the Expanded Universe novels, result in drastic improvements. Cortana, for example, analyzes the tech and uses it against the Covenant by converting a plasma torpedo launcher on a ship they hijacked into a Wave Motion Gun by simply recalibrating its programming. This turned out to be not so beneficial when the rogue Covenant AI on that ship managed to send the information about the improvements out to other ships in the area.
The inability of the Covenant to use their technology is made very obvious in the manual with the Halo 2 collector's edition, where the Covenant hierarchy themselves state they have no way of recharging plasma weapons in the field, and all Covenant troops are trained to throw away a depleted weapon and take a charged one off their dead comrades.
In the Mass Effect series, the Citadel and mass relays are thought to be built by the Protheans. Humans and other races use them, though their inner workings and construction are poorly understood, and any attempt to understand them is regarded as an exercise in futility. It turns out that a race of Abusive Precursors, the Reapers, were the real builders of these wonders, and the Protheans were just barely figuring out the technology themselves when they were wiped out.
Worse than that, the mass relays and Citadel are a huge trap set by the Reapers meant to alert them when sentient life is ready for another round of reaping. Just before they begin their invasion, they disable the entire relay network so that all star systems are isolated from each other, and ripe for the picking.
Matriarch Aethyta very much dislikes the black box nature of the relays and once proposed trying to study relays more intimately, maybe even building one. As she puts it, the other Matriarchs "laughed the blue off my ass."
The design of their conventional FTL system is much the same, being almost entirely reverse-engineered from the Protheans. This means that they have no idea how to disengage certain safety protocols that prevent ships from being flown into planets or other vessels at relativistic velocities. While this is generally a good thing, it prevents the military from using this tactic against the Reapers.
The third game kicks this Up to Eleven with the Crucible, a light flung into the future so many times that barely anyone who tried to build it understood what it was or what it did. Not even the Protheans were sure how it even operated, and they nearly finished the damn thing before the Reapers completed their invasion. It's hammered home numerous times through the game that it could do damn near anything because while there are easily understandable blueprints for it, there's no data on how to use it or what it does. At one point Commander Shepard likens the situation to a child playing with his father's gun.
Not only that, but the in game resource "Tiberium" which acts as the catalyst for the entire series is an alien terraforming plant that will shape earth to become like their planet. In their attempts to study the plant both sides find ways to turn it into a weapon.
In Sins of a Solar Empire, the Advent field Phase Inhibitors stolen from the TEC, who use Phase Inhibitors captured from the Vasari. . . who also don't know how Phase Inhibitors work, and simply field copies of ones that they found.
The Metroid Prime subseries involves the use of Phazon, a blue gooey substance that turns its users Nigh Invulnerable and greatly amplifies their weapon strength. It also corrupts its users into willing slaves of the host planet Phaaze, but thems the breaks!
The PED suit from Metroid Prime 3 contains a "black box" that allows the user to boost their power with Phazon, though how the corruption is contained is not explicitly stated. Samus's black box breaks early in the game.
Samus's suit has tons of hidden properties the Chozo didn't have time to tell her. Fortunately the suit is smart enough to do that for them. Not only that, but the suit is actually capable of using non-Chozo technology to upgrade itself when Samus acquires it, which gets really strange when she picks up Luminoth, Space Pirate and human technology (though human power suits are most likely based off Chozo power suits anyway).
In Prime, Space Pirate documents specifically make mention of their utter bafflement by many of the suit's functions. They have also been attempting to reverse-engineer aspects of her suit, such as the morph ball. In that particular example, their tests with a live pilot produced unfavorable results.
Played with in Homeworld, whose Historical and Technical Briefing describes the discovery of a large amount of Lost Technology in the wreck of an ancient spacecraft, including something eventually identified as "a solid-state hyperspace induction module". It's implied that much of their limited understanding of how it actually works was gained from building a couple of scaled-down copies and fitting them to small spacecraft, pressing the 'on' button and watching to see what happened.
Then it turned out that said module is actually a 10,000-year old Progenitor Far Jumper; only three of them exist in the whole galaxy. One of these are in the posession of the Bentusi and it's the basis of all hyperdrives in the galaxy, save the Kushan ones. It is also said that no matter how much they study them, they can't figure out why the reverse-engineered versions are much slower than the originals even though they know how to make other ships tag along by "riding the quantum wavefront". In fact, combining the three Far Jumpers will break the laws of physics (black holes disable hyperdrives yet the Trinity still works flawlessly).
In the TouhouExpanded Universe, there's a character named Rinnosuke. Rinnosuke has the power to immediately identify the function of any device he sees. This does not mean that he knows how to use it. (He sometimes gets strange results too, like identifying a Nintendo Gameboy as a "World Controlling Device," but that's a different trope.)
The Metal Max series has this in spades. Aside from the world having been wrecked so badly no one even remembers what several machines DO, let alone how to build them (tanks among them - although The Disassembler seems to know his way around them, but he's insane and only disassembles them, hence the name), there's the androids Scarlet and Alpha in Metal Saga, whom nobody knows how to fix (hence why if Alpha gets KOed, she can't be revived, and why Scarlet dies after you defeat her - she's been going without repairs since the Great War that wiped the planet, and her regeneration is pretty much at its limit, she even comments on it being the case). The genetically engineered dogs in Metal Saga may also count, as they are very clearly far more intelligent than they appear, bordering on being smarter than quite a few humans.
Dwarf Fortress, reportedly, is one. Not only is Toady One very protective of the source code behind his masterwork, but his software development skills are almost entirely self-taught. The handful of people who have been entrusted with backup copies of it have attested that the code is almost impenetrable to mere mortals.
Really, this can apply to just about anything a player creates in the game. Fortresses can get so elaborate that critical functions are simply forgotten or change completely as they are built upon. Many a fortress has run into fun because the guy running it forgets which lever opens the door to the mess hall and which one activates the fortress' lava-based self-destruct. A truly stand-out example has to be where one Let's Play ended up creating a fortress so convoluted that one room ended up becoming its own Pocket Dimension.
The superweapons of the Naval Ops series, especially in Warship Gunner 2, are considered to be Black Boxes by the people fighting against them. In WG 2, they run off a Black Box "Engine" strapped into oversized conventional ships (for a given value of conventional).
Deadliar from Hellsinker previous nickname was Blackbox in true spirit of this this trope since noone had any idea how he operated and produced the results he did.
In a flashback arc of Gnoph, a scientist criticizes the military for creating a breed of Super Soldier pretty much by accident and then using them despite not really understanding how or why they work. Sure enough, things soon Go Horribly Wrong.
Dr. Westman: Gotta love that military mentality: "Ah don' know why ut works, but they sure do kill!" Idiots.
According to Word Of God, the Beam swords in Exterminatus Now are Lost Technology from a long-gone empire, and are not comparable to any other technology (modern or otherwise) in the setting (so the dark Machine God cannot possess them). This goes a way towards explaining why the Forgemaster who builds them is ignorant and suspicious of modern plumbing.
Some government agents in Real Life Comics once confiscated an interplanetary ship Tony made. They opened up the reactor and found . . . jam.
Nobody Scores had an arc where the main characters ended up getting their hands on a literal black box — things went in, and other things came out. It was when it started producing multiple copies of the severed head of Shia LaBoeuf (who was still alive) that they started trying to get rid of it...
In Gunnerkrigg Court, Anja and Donald Donlan created a computer that runs on magic, which even they don't fully understand the workings of. They're the only ones who use it—the rest of the Court distrusts it precisely because it's a Black Box.
Diego's Super Prototype robots (which also appear to run on a combination of magic and technology) are also black boxes. They have no visible power source, nor means of moving their limbs. They are golems made by a master mechanician who wrote their "OS" in what under a magnifying glass turns out to be a small book worth of runes. Modern robots are black boxes even while self-documenting. When asked to print their operating code, one produced a 3D image of some complex structure made of runes, with density requiring a microscope to read, without any sort of map legend, and neither derived from nor designed to be compatible with, any human languages, natural or programming (they are robot-built).
An early Goats storyline involves such a machine - you put kittens in, and pop tarts come out; nobody knows what happens to the kittens. Later it's revealed that the machine is a stolen alien spaceship engine, which is powered by the good feelings created when the kitten is placed in a loving home. But it's still a Black Box, because even the aliens don't know where the pop tarts come from.
In Westward, Escherspace — a form of Faster Than Light Travel — appears to be a Black Box. Publicly, the government claims that "only a few scientists" know how it works; in reality, it's strongly hinted that only the mysterious alien Phobos may be capable of understanding it, and he must personally work the controls when the webcomic's eponymous Cool Starship makes an interstellar jump.
In Spacetrawler, it's implied that the eponymous spacetrawlers (which the entire galaxy relies on to enable faster-than-light travel and matter synthesis from space debris) are so complicated that only the technopath Eebs can understand and construct them. It's eventually revealed that their construction is less complicated than implied, but the details are so horrific that it's no surprise that the builders insist on keeping them secret.
During the "Star Trek" parody arc of Quentyn Quinn, Space Ranger Omnibus described the devices running the essential functions on the "Glorious Undertaking" as "black box" devices. Turns out they were cosmic entity tech secretly installed by "Cue" to limit the number of exploding Federation vessels.
Most of the super-advanced technology in the Orion's Arm universe is at least partly powered by transapientech. This is by definition designed by beings orders of magnitude smarter than ordinary folks. This is something of a subversion in that the inner workings are completely known, and probably published somewhere on the net, but the people using them can't understand them, since their brains aren't complex enough. It's sort of like trying to teach a small child nuclear physics in depth.
Some artifacts in custody of the SCP Foundation. Anything classified as "euclid" is not entirely understood by the Foundation staff, though some Safe-class objects, such as SCP-914, also display this sort of behavior.
Ben 10's Omnitrix. Not from earth. Seemingly simple to use on the surface... But it has secrets, hidden abilities, glitches, and occasionally, a mind of its own.
Eventually they meet its creator, who doesn't seem to understand what he's built either.
He fully understands it's inner workings, it's just that he's very reluctant about revealing them to other people.
In WW II, at a time when electronics were evolving rapidly (e.g. microwave/RADAR technology), the British assembled electronic parts into random yet convincing circuits, then shot and otherwise mangled them, then let their bombers carry them. If one of them was downed, the Germans would go through the wreckage, find the remains and then spend valuable time and manpower to try to figure out what this secret device was supposed to do.
On Doctor Who, one of the companions, Kamelion, was, behind the scenes, an actual, animatronic robot. Unfortunately, the person who had designed it and who knew the control codes died after the episode where it first appeared, so the character mostly had to stay in the background.
The Jargon File and its dead-tree twin, The New Hacker's Dictionary, is rife with terms describing programming Black Boxes, most notably Black Magic.
The most memorable of which is the "Magic / More Magic" switch. The only wire soldered to the switch goes directly to the case of a server. There is electrically no way it can affect anything on the server (except for EXTREMELY bizarre capacitance effects), and yet switching to "Magic" causes the server to die.
It could also be due to a difference in electric potential between the ground and the case.
Black Box programming is a very important concept in real life. For example, all APIs (which allow developers to connect to things like Facebook or Google Maps) are black boxes; generally, the only details developers have are usage instructions and a description of what it does, since someone writing, say, a GPS application doesn't need to know anything about how Google Maps works.
In this case, this is actually considered a good thing: abstraction means compatibility. If your software is designed without using any knowledge of how the black box part works, it will (at least in theory) be possible to swap that library out for an updated or improved version later on. So long as somebody knows how it works, it's just a matter of trusting one's fellow engineers. In contrast, the moment you have to know how each variant of something really works instead of just one set of common operations, a task that should be trivial turns into a nightmare. Remember those DOS games and their sound setup programs?
In object-oriented programming, objects are supposed to be black boxes, often having public and private groups of variables and functions. The "client" only need to know what the functions do and what should be put in the variables, and not anything about the inner workings. Similarly, template libraries and built-in functions in many programming languages (like C++'s STL) are Black Boxes. The documentation on C++'s sort() function, for example, doesn't tell you what kind of sorting algorithm is used, because it doesn't really matter (although one can deduce that it's probably a quicksort implementation from what they say about its running time).
And if someone else wants the class to do something else, the chances are they'll write another class that extends and/or calls the old one, rather than trying to rewrite the existing source code.
Large amounts of real world software source code is an absolute abomination of incomprehensible abbreviations, architectures which haven't evolved and grown so much as become cancerous, baffling hacks and plain old carelessness and stupidity or even just plain old lack of programming know-how. Such software will gain Black Box status pretty soon after the original developers move on.
Fun fact: Masi Oka (yes, Hiro from Heroes) still has to do occasional effects work for his former employer, ILM, because nobody else knows how to use his software.
This isn't unusual. Truly understanding non-trivial code written by someone else without documentation is considered the mark of a master programmer. It's said engineers don't retire, they just become consultants and come back to fix their old things when they break.
Particularly this is true of cryptographic algorithms. You put plain text and encryption key in, and you get back line noise. Put line noise and decryption key in, and you get back plain text. Unfortunately so few people actually understand the algorithms and code that, even in open source software, bugs can lurk for a long time.
More humorous example, in an attempt to cut government costs, California decided to fire a large chunk of government workers, then redo the pay rates for everyone left. Well, phase one went off fine, but come phase two they realized that every single person that knew enough about the payroll software to implement the changes was fired in phase one.
Older electronic (and most especially military) technologies may well have been designed by people who are dead, coded in languages which no-one ever hears of nowadays, use electronic standards long since obsoleted and built by companies that dissolved or got eaten by other companies some time ago. Black Boxhood arrives quite naturally for such devices, which could conceivably include missile guidance systems or nuclear warhead triggers which are still quite useable today.
COBOL used to be a very common language for developing business software in. Though superseded by modern languages like Java or Visual Basic, old working software was not replaced. The pool of skilled COBOL engineers is rapidly dwindling simply because they are retiring and in due course upgrade and maintenance engineers will simply not exist anymore.
It seems that the original programming of Microsoft Excel might be a black box, since after the principal programmer quit, the project virtually stopped. Luckily he came back.
Many psychiatric drugs work via mechanisms that are either unknown or only loosely understood. The laborious (sometimes decades long) process of searching for side effects and other quirks irons out many of the Black Box problems that plague fiction.
On that subject, some (if not most) chemical reactions in general have mechanisms which are only vaguely understood at best.
Real Life is rife with stories of a programmer being fired for whatever reason, only for his ex-boss to realize nobody knows how to maintain the server.
Due to the "digital rights" controversy, certain laws have been put into effect that require black boxes to remain black boxes, making it illegal even to try to crack into them. For example, it's now illegal to write programs to get past certain types of encoding on music, DVD's, and electronic books. If you have even a slight understanding of the way technology progresses, you'll probably see this move as either "stupid" or "scary", possibly both.
If you've followed the results, "laughable" "doomed" and "legally unenforceable" are more likely.
Older Than Radio: During the early 18th century, Antonio Stradivari hand-crafted several wooden violins that, compared to other violins before or since, produce the highest-quality sound. Many violin manufacturers have, for centuries, attempted to not only replicate the sound of the Stradivarius, but have even labeled violins as "Stradivarius" as a marketing ploy. Unfortunately, when Stradivari died, the technology and skill required to produce a violin of such caliber died with him. Scientists continually do research on the Stradivarius sound and technologies to replicate that sound, and original Stradivarius violins remain to be the most valuable musical instruments in the world.
The "Stradivarius" label on violin is not there for marketing reasons. It's actually a model of violin - Antonio Stradivari's instruments had very specific proportions (also being slightly larger than ones made by competing crafters). If you see a violin labeled "Stradivari", it means that its proportions and size match those of an original Stradivari instrument.
It has been speculated that the sound quality is due to the wood available at the time. He built them around the little ice age, and wood at that time was particularly thin and brittle due to the odd weather patterns, making them irreproduceable. On the other hand, other violin makers of the time were unable to reproduce it either.
There's also evidence that Stradivari violins aren't that great in the first place.
The philosophy of instrumentalism boils down to "the only important thing about any theory is whether it's usable, i.e. predicts a result of given experiment". Hunting for explanations is but a pointless infinite regression. This means that "light is truly made of particles" and "light is truly made of waves" are fancy statements that delusionally bind real events to imaginary constructs while "wave model correctly and in convenient form predicts diffraction/interference effects" or "particle model correctly and in convenient form predicts absorption/emission effects" states everything that really matters in this issue. From this point of view anything is a Black Box, the only difference is that we already know how to dismantle some blackboxes to several smaller blackboxes and what buttons to push.
Arguably the universe itself is a black box since we don't (yet) have a complete physical theory of the universe. Also, while we do have two theories that work fine in their respective arenas (General Relativity: big and heavy stuff, Quantum Mechanics: small and light stuff), they are contradictory and become completely incomprehensible when used together.
There's also an older theory called classical Newtonian mechanics, which works for medium-size and medium-mass stuff. It was specifically created to avert this trope and describe a Universe governed by simple, understandable laws; it failed at that. However, it works nicely for 90% of the stuff we encounter in our lives, and that's why it, and not GR or quantum is taught at schools.
The plans for the Saturn V rocket from the Apollo Project are stored in a format that isn't readable by any computer currently in use. Since there are a few leftover rockets, that could potentially be fueled up and fired, they have become black boxes. When the new designs for the Orion spacecraft (not the nuclear-bomb one, the newer one) were in the works, the ability to look at the old Saturn design and learn from them was denied the engineers, who had to waste potentially years starting from scratch. Since then, to avoid this trope, a project was initiated to attempt to retrieve the data and transfer it onto a more modern storage medium, but it's so underfunded that it's not currently active.
Although some of that is true, there are other significant factors involved - for instance, not being allowed to use asbestos anymore even though we know how. It's not purely a case of "no longer able to read the plans."
This is an urban myth. The Saturn V plans are stored on microfilm. While readers are not nearly as commonplace as they were at the time of the rocket's conception, they're still readily available.
Though microfilms do exist, several key parts were destroyed due to Cold War policies on classified materials. The Orion engineers also had access to the engines from one of the original (IXX, I think) F1 engines taken from the rocket currently displayed at the Marshall Space Center in Huntsville, Alabama.
The engineers also have to look in junkyards for intact components from the old program in order to try to figure out how they work.
Nikola Tesla, thanks to a heady mixture of personal eccentricities, outlandish claims, and industrial FUD both during and after his time, has a reputation for this sort of thing rivaled only by fiction. All his well-documented inventions work from explicable, if clever, principles of engineering — but poorly documented claims abound of death rays, earthquake generators, and yet stranger things unreproducible by modern science.
The fact his documented ideas tended to get stolen (usually by Edison) might have something to do with it.
SR-71 Blackbird recon plane: Due to ongoing modifications to their respective airframes each Blackbird had its own set of blueprints. Thus, each Blackbird was unique, although they do looked identical. The original molds or dies used in the manufacturing of the planes were ordered destroyed by then Secretary of Defense McNamara (Cold War policies again) so it would be nearly imposible to make new Blackbirds or even spare parts (In fact other airframes had to be cannibalized to keep the fleet airworthy), although a lot of planes survive to this day so reverse engineering could be feasible.
The human body itself is quite the black box. With the exception of your occasional doctor or biologist, everyone uses theirs without the slightest hint of how the lot of it works. The brain in particular is quite the mystery, for if it was simple enough we could easily understand it, we would be unable to do exactly that.
While there is still debate on the subject, nobody knows for sure why a bicycle stays upright when you ride it. It just does. Numerous theories have been put forth with some of them holding water. See this Cracked article.
The same article also lists several other questions that even modern science can't answer: why we sleep, how many planets are in the Solar System, why ice is slippery, how to beat Solitaire, how many animal species exist, what is the length of the US (or any) coastline, how does gravity work. A lot of these questions that we just either never ask or accept a universally-known explanation, which is actually false.
Some of these are somewhat trivial, while others are more interesting. How many planets are in the Solar System depends on one's definition of planet - it isn't the result of lack of knowledge but rather of definition, and if we mean a -real- planet, not a minor one, the answer is pretty clear at 8 - while it is possible we will find a far flung planet in the solar system, it would be pretty remote (there certainly isn't a planet anywhere nearby, and the vulcanoids are not hiding a planet), and this is simply mistaking science for something else (nothing is ever proven in science, after all). The length of any coastline depends on your level of precision. And while we don't know exactly -why- ice is slippery in the sense of not knowing what causes it, we are pretty sure we know the cause of the low friction - a thin layer of water on the surface. On the other hand, we really don't know why we sleep, how gravity works, how many species there are (though like the planets one, this is more of a lack of total knowledge than a lack of theory, which is a very different thing), why bicycles stay upright (sort of... we do know some of this, at least the obvious bits, but there are clearly more factors at work)... it's a bit awkward that the article mixes two things (knowledge questions vs theory questions), as there are lots of knowledge questions unknown to science.
There was a fad for "miracle cure" machines at the beginning of the twentieth century that were actually called Black Box machines. You just set a few controls, turned it on, and whatever quack therapy that model was based on would cure the illness. The reason they were intentionally kept as black boxes was the controls did nothing to its function, and most in fact had no working parts.
Any self-taught coder will make these whenever they program....well anything. How bad it is depends on the degree of "self-taughtedness".
This situation tends to happen whenever a nation receives exported military equipment from another nation's military (planes, tanks, ships etc.) and something sours political relations between them. A sudden change in government, or an embargo due to some unsavory incident can effectively turn a chunk of a nation's military into a black box. No longer getting the support in terms of maintenance to keep them in service or upgrades to keep them relevant, the material in question rapidly becomes warehoused for fear of damaging it beyond repair or obsolete. Solutions are varied, ranging from reverse-engineering, putting in locally-made upgrades, producing their own replacements or getting a replacement from another friendly nation. Examples include the F-14's Iran received before the Shah was overthrown and various helicopter models China received just before the Tienanmen Square incident.
For a very common (and far more mundane) example, many, if not most, things that people use day-to-day are effectively black boxes. There is an oft-quoted analogy about how the ability to drive a car does not equate an ability to design and build a car, or even to fix one. For a fun thinking exercise, see if you can actually explain the workings of a microwave oven, or a computer, or a cell phone, or any other number of things you use daily.
In biology, the occasional black box arises in the form of a living organism. For example, of the twenty or so species of beaked whale known to science, about three are well documented. The rest are very poorly understood, some of which we haven't even seen living specimens of yet. Where they live, how they breed, what they eat, how deep they dive, none of these are known. We know that they exist because we have dead bodies (for a while, one species was known only by a jawbone), but how they exist is largely a mystery.
For much of the Cold War, nuclear weapons were black boxes, either entirely or to the people working with them. All nukes were designed by multiple people, but sometimes these teams worked loosely with each other in isolation, the effect being that no one person knew how a particular nuclear weapon worked. This method of security eventually fell out of favor as some of the bombs produced by these teams were abject failures; to the extent that at one point in US history, nearly all the warheads carried by US submarines were dudes due to their faulty safety systems. In the other case of nuclear black boxes, teams designing ICB Ms and bomb cases were given the bare minimum of information needed to design a delivery system.
Several of the computer rankings that make up the Bowl Championship Series formula in college football are proprietary. Accordingly, no one exactly knows why they would rank the teams in the way they do, and major bowl bids (and millions of dollars) can hinge on the result.