Conway's Game of Life (sometimes called "The Game of Life", although that can be confused with a board game of the same name, or simply "Life"), is a cellular automaton, a type of system in which rules are applied to cells in a grid. It's not a game in the sense that one can win or lose, but it can be considered to be a zero-player game. In other words, the initial configuration determines the result, without any input from any "players".

Conway's Game of Life is played in an infinite grid consisting of square cells. Each cell can be in one of two states: "living" and "dead." The configuration changes from one turn, or "generation," to the next based on the following rules:

- Any living cell with less than two neighbours becomes a dead cell (you could think of it as dying due to underpopulation, if you like).
- Any living cell with more than three neighbours becomes a dead cell (you could think of it as dying due to overcrowding).
- Any dead cell with exactly three neighbours becomes a living cell.

Note that all of the changes from one generation to the next are handled simultaneously.

Conway's Game of Life can result in many interesting patterns. If you'd like to try to make your own, see Game of Life simulator on this site's sister site, All Fun and Games.