Cellular automata are a central example of Stephen Wolfram's science, and of simple programs in the computational universe. Explore some of their amazingly rich and varied behavior here. See Wolfram's rule 30, and then choose more colors to explore rules that have probably never been seen before.
Stephen Wolfram explored these one-dimensional cellular automata in his classic computer experiments beginning in the early 1980s. Discoveries about these systems led to his book A New Kind of Science.