The Game of Life (often referred to as "Conway's Game of Life" for clarity, or just "Life" for short) is not, technically, a game (or if it is, it's a zero-player game with no objective). The title is a somewhat romantic way of referring to a specific cellular automaton invented by mathematician John Conway in 1970.
A cellular automaton is a large grid of simple "cells", each of which has a state that can change depending on how it interacts with its neighbors. In the case of the Game of Life, the rules are extremely simple:
- Each cell can be either alive (on) or dead (off).
- If a dead cell has exactly 3 neighboring cells, it becomes alive (birth).
- If a live cell has either 2 or 3 neighboring cells, it stays alive (survival).
- In all other situations, a cell dies (or remains dead).
Although these rules are trivial, the surprise of the Game of Life is that the resulting cell interactions are remarkably complex. From the chaotic interactions, stable patterns can be seen to form; tiny formations of cells that stabilise each other, oscillating formations that "blink" over and over, and perhaps most interesting of all, cell formations that can move, autonomously of other cells. The Game of Life could be considered a simulation of a unique "universe" with its own physical laws.
By carefully arranging cells in the Game of Life, it is even possible to build new things; "guns" which fire streams of "gliders" continuously, "reflectors" which can bounce gliders around, patterns that grow continuously, and more. Eventually, it was discovered that one can implement logical structures in the Game of Life and build a universal computer; that is, the Game of Life is Turing-complete. Conway also proved that it is possible to create a universal constructor in the Game of Life; that is, a pattern that can construct other patterns, including itself. Various attempts have been made to build such self-replicators.
Even decades later, the Game of Life has a strong hobbyist following, and new discoveries are still being made.
A website which allows you to tinker around with Life patterns can be found here.
- Follow the Leader: The Game of Life is one of a distinct class of cellular automata: to be specific, it is a 2-dimensional, 2-state, orthogonal, outer-totalistic cellular automaton that obeys the B3/S23 rule within a Moore neighborhood. The "B3/S23" is the important part, as that's the encoding of the birth/survival rules that give Life its uniquely dynamic properties. However, there are a vast number of other rules that can also be used, and many of these have been explored too. In honor of the Game of Life, they are referred to as "Life-likes".
- Trope Codifier: The Game of Life was not the first cellular automaton - the concept originated in the 1940s, and the first actual cellular automaton was devised by John von Neumann in the 1950s. However, Conway's automaton is the best-known and most widely explored. Part of this is due to its simplicity: the automaton can be summed up in just a few sentences and implemented in only a few lines of code.
- Video Game Cruelty Potential: Patterns in Life are extremely fragile; adding or removing just one cell to a stable pattern is generally enough to destabilize it such that it completely unravels and decomposes into a chaotic mess.
- Wrap Around: It is common for implementations of the Life grid to wrap around at the edges, as otherwise the edge of the grid can interfere with the automaton (a cell at the edge can only have at most 5 neighbors, or 3 in the corners).
References in fictional works:
- Tea With The Black Dragon by R. A. MacAvoy has a metaphorically-significant scene in which the protagonist is introduced to the game.
- Kingdom of Loathing has a mushroom farming minigame that follows the same rules (although with more than one kind of mushroom), but the board is only 4x4, making it impossible to create any particularly interesting patterns.
- Square Root of Minus Garfield's "Garfield, Infinite Canvas, and The Game of Life", in which a Garfield comic about not having a life is used as the starting state for the Game of Life.
- Glory Season by David Brin features this game with the variation of being played as a contest, with each side getting part of the board to use, with the goal being eliminating the other side.
- One of the intro cinematics for Darwinia is a simulation of Life, with the added caveats that the grid is confined to a finite space and each Darwinian will die after a set number of years no matter what. As it's incredibly difficult not to get attached to the little guys while playing Darwinia, seeing the last "block" and "spaceship" formations settle, flicker, and die can be very haunting. In-universe, it was given to the Darwinians to teach them mortality.
- An element in the Boulder Dash clone Rocks N Diamonds.
- In Lyndon Hardy's 1988 novel Riddle of the Seven Realms, a character creates a dimension that operates under these rules, even calling it "the realm of the conways."
- Entering the cheat "gol" in SimCity 4 plays the Game of Life using SimCity 4's grid-based lot system.
- Revival "Game of Life" is a spellcard used by Eirin Yagokoro in Touhou 8: Imperishable Night. Word of God commentary makes reference to the bullet patterns being inspired by those found in Conway's Game of Life.ZUN: "You might not understand this if you didn't study at a technical college."
- In System Shock, the walls, floors and ceilings of the virtual Cyber Space environment are square grids that light up in patterns that are seemingly arbitrary, until you realize they're following rules from the Game of Life.
- In ADOM, herbs grow this way. With the right preparations, you can grow an near-infinite number of herbs in the "Big Room" of the Caverns of Chaos.
- The WWW Trilogy's first book has Caitlin seeing cellular automata in the background of her "websight;" Dr. Kuroda brings up the Game of Life as an example of cellular automata while explaining it.
- The Orion's Arm Project has, among artifacts of unclear origin, a planet sized Life field. Apparently, it's been played long enough for life to evolve in the game.