This is a video showing the operation of a spaceship gun in Conway's Game of Life, a simple set of rules invented in 1967 by John Horton Conway, a Cambridge mathematician. Conway's Game of Life is designed to simulate cellular automata. The amazingly intricate movements, patterns, and processes such as this spaceship gun are all the result of four rules:

For a space that is 'populated':
* Each cell with one or no neighbors dies, as if by loneliness.
* Each cell with four or more neighbors dies, as if by overpopulation.
* Each cell with two or three neighbors survives.

For a space that is 'empty' or 'unpopulated'
* Each cell with three neighbors becomes populated.

The usage possibilities associated with these simple rules are endless and new discoveries are being made constantly.

This video is a screen capture from Golly, a program that simulates Conway's Game of Life and other cellular automata rule sets.