This runs the algorithm called "The game of life." I am fascinated by how technology can fake life.

Life applet:

The rules are:
An empty cell will be filled ("born") if at least 3 of its neighbors are filled.
A live cell will die if it has less than 2 live neighbors (it dies from loneliness), or if there are more than 3 live neighbors (too crowded).

You can use the mouse to fill and clear cells and there are settings for the zoom factor and speed. Also a run/stop button.

This program stolen from: www.gradient.org.