Below is a little animated gif I made last night for this page.

Image: A simple configuration in von Neumann's cellular automaton[1]. A binary signal is passed repeatedly around the blue wire loop. The diamond cell duplicates the signal onto a length of red wire. The signal passes down this wire and constructs a new cell at the end. This particular signal (1011) codes for another red arrow, thus extending the red wire by one cell each time. During construction, the new cell passes through several transition states, directed by the binary sequence.

This is the underlying mechanism behind the self-reproducing machine I posted about last time. It's a bit like inside a computer but one where the electrons drop out of the end of the wires and lay down new parts.

This was the first ever cellular automaton. You've probably seen the Game of Life but this is older!

This post was originally on LiveJournal.