The applet on this page shows a grid of colored squares. Initially, all the squares are the same color. One square is selected at random, one of the four neighbors of that square is selected at random, and then the color of the selected square is converted to the color of its selected neighbor. This is repeated indefinitely. (Note that for the purpose of determining neighbors, the top edge is considered to be connected to the bottom edge, and the left edge is considered to be connected to the right edge.)