Wireworld Cellular Automaton (1987)

Proposed by Brian Silverman, Wireworld is Turing-complete, meaning it can compute anything a computer can. It has only 4 states:
1. Empty Background (.)
2. Electron Head (H)
3. Electron Tail (T)
4. Conductor (+)
Rules: A head becomes a tail. A tail becomes a conductor. A conductor becomes a head if 1 or 2 of its neighbors are heads.
This simulation shows a clock generator feeding into two diodes and a simple delay loop.