A dangerous pastime, I know ...
Now the wheels in my head have been turning ...
And right now I'm evolving a plan
Sometimes, people have to think long and hard about something, whether it be a common problem or a moral dilemma. When they do, there is a chance that a set of wheels (usually gears) will appear in their heads. This can be attributed to the comparison between the human brain and a machine at work, such as a clock. It can also be a sign of a character's intelligence, as they are likely to be thinking almost constantly. Alternatively, a very small and/or poorly functioning set of gears could be depicted to indicate stupidity.
This isn't always a visual trope, as there are verbal expressions that carry this image.
Compare Idea Bulb, where a light bulb appears after the character has finished thinking.
- The Close Shaves of Pauline Peril: Snodgrass McViper usually gets these when coming up with a scheme to get rid of Pauline. He literally ground gears on his head in the fourth issue, though it was likely just a visual gag.
- Deadpool: One story in Baby's First Deadpool Book finds Deadpool and Blarney the dinosaur in snow-covered mountains. Deadpool gets hungry and asks Blarney to cut off his tail for food. As Blarney ponders whether he should, a set of gears appears in his head, with tiny Blarneys to boot.
- Metal Men: The cover of the fourth volume's final issue shows each of the Metal Men being a gear inside the head of their creator, Doc Magnus.
- Tintin: The Red Sea Sharks uses a combination of this trope and Rebus Bubble. Tintin tries to wake up a snoring Captain Haddock before they're caught by a patrol. He uncorks a flask of rum, which the captain hears, and his thoughts turn to gears as the sound of a cork leads to the thought of bottles of whiskey. He wakes up, downs the flask in a single gulp, and gets ready to fight the patrol before Tintin convinces him otherwise. For a better idea: "Pop" = picture of cork and gears = picture of bottle and gears = "Whisky".
- In "Mystery Meat," a WordGirl comic story, the Butcher's plan is foiled because his meat attacks don't work against Captain Huggyface. When he tries to think of where to find a book containing recipes that Captain Huggyface wouldn't like, turning gears appear next to his head.
- A variant in Scott Pilgrim vs. The World. When Ramona learns that Knives is Scott's ex-girlfriend, the first question she asks him is how old Knives is. The camera zooms inside Scott's head where a roulette wheel spins through various potential responses; it eventually stops halfway between "I gotta pee" and "Who, her?"
Scott: I gotta pee on her... I mean, I gotta pee. Pee time.
- The Lord of the Rings: Other characters describe Saruman as having "a mind of metal and wheels", as a poetic criticism of his preoccupation with efficiency and industrialisation and his reckless disregard for people.
- The Machineries of Empire: The undead Evil Genius Nirai Kujen appears as an abnormal shadow on his human host, full of intricate gears that transform to and from the Nirai faction's Macabre Moth Motif as they spin.
- Mother Night: Campbell uses an extended gears analogy to describe the totalitarian mind.
I have never seen a more sublime demonstration of the totalitarian mind, a mind which might be likened unto a system of gears whose teeth have been filed off at random. Such a snaggle-toothed thought machine, driven by a standard or even a substandard libido, whirls with the jerky, noisy, gaudy pointlessness of a cuckoo clock in Hell....
- The Honeymooners: In "The Sleepwalker", Ralph has to spend the night with Ed and keep him from sleepwalking out of the room. At one point, as they bed down for the night, Ralph takes special precautions by locking themselves in the room and hiding the key where Ed can't get to it. Ed comments on his friend's strategy: "The wheels are turning up there tonight, boy." As he says this, he makes a turning motion with his finger.
- In the first Animal Crossing game, during a conversation, animals will occasionally pause for thought with a little animation of gears ticking over their head, complete with the sound of a clock ticking. Later entries replaced this with an animated ellipse inside a thought bubble.
- Spandex Force: The mind icon is represented by a gray head with gears in it.
- Rooster Teeth Animated Adventures: In "Booger's Big Blowout," Chris recalls when his dog Booger had diarrhea in the car and got some on himself. Between freaking out, Booger is shown looking at his tied leash with gears in his head, trying to figure out what to do since he can't move too much.
- Wooden Plank Studios
- In "Pywrath," Mythra gets this when meeting Sephiroth, remembering that he sent a fake Smash invitation to Rex. She then switches to Pyra, who caves his skull in with her sword.
- In "Cranky King," Kazuya and Incineroar need Life Balloons from Cranky Kong to revive Donkey Kong and Diddy Kong, but have no Banana Coins to buy them. Cranky gets some gears when asked if he'll accept another form of payment. He settles for Kazuya's pants and what's left of Incineroar's fur.
- Adventures of Sonic the Hedgehog: When a local Merman is demonstrating how the explosive Power Pearls work, Sonic gets these before realizing they should run away before they go off.
- Beavis and Butt-Head: When Beavis is shown thinking, the gears in his head are missing pieces and squeak while they turn, as if they were poorly maintained.
- The Grim Adventures of Billy & Mandy: In "Hoss Delgado: Spectral Exterminator", Hoss tries to destroy Grim for holding Billy and Mandy hostage, until Grim tells him it's the other way around. When trying to comprehend, the inside of Hoss' head shows a mouse running on a hamster wheel.
- Larry & Steve is a concept "pitch" cartoon by Seth MacFarlane about a dimwit named Larry that adopts an intelligent dog named Steve. Arriving at Larry's home, Steve notes some deficiencies in the decor, and mentions that these problems need to be addressed. The thought balloon above Larry starts with two cogs meshing, but slowly and with much creaking, followed by a square peg failing to nestle into a round socket. Clearly, Larry doesn't do thinking very well.
- One episode of Mr. Baby has gears shown inside Rudy's head.
- In the opening sequence of Pinky and the Brain, which is also derived from their segment on Animaniacs, the inside of the two mice's heads are shown when they pass by an X-ray machine; while Pinky has a peanut inside his head, Brain has turning gears in his.
- SpongeBob SquarePants
- In "Patrick SmartPants", the top of Patrick's head comes off after he falls off a cliff. When SpongeBob replaces it, the brain plugs into its socket, causing the cobweb-covered gears to spin and make the starfish intelligent.
- In "Sing a Song of Patrick", Patrick tries to write a song. He gets the underused gears in his brain to work, though he is clearly straining. They also produce a foul-smelling smoke detected by Squidward.
Squidward: What is that horrible smell? Is Patrick thinking again?
- Zig & Sharko: In "Magical Jellyfish", Sharko takes the jellyfish (transformed to look like Marina) from Zig, who attempted to switch it with the real Marina. When Sharko tries to figure out which Marina is the real one, turning gears appear over his head.