Game of Life

I saw John Conway's Game of Life on Stephen Hawking's "Grand Design" on Discovery Channel.

http://www.bitstorm.org/gameoflife/
http://en.wikipedia.org/wiki/Conway%27s_Game_of_Life
 
The game is played on a cellular grid.  Each cell may be living or not.  What happens to it depends on its neighbors. 

If a living cell is in contact with only one or two other living cells, it dies of loneliness.
If a living cell is in contact with four or more other living cells, it dies of overcrowding.
If a living cell is in contact with two or three other living cells, it survives.

If a non-living cell becomes contacted by three living cells, it is born.

The population may start small, grow, die out, become static or oscillating.  If an "immigrant" is added to a static population, it may grow again or be destroyed and disappear.  Static populations may consist of isolated groups, which may be energized by adding "immigrants" and recontact each other. The population may survive many generations of growth and depletion, before becoming dormant or dying out.

It's called the Game of Life, because of the many parallels to natural populations and the suggestion that human thought patterns may operate the same way, based on simple rules, with many repetitions of the same pattern.