DEFINITION
off → firing with exactly 2 firing neighbours firing → refractory → off (Moore neighbourhood)
NOTES
Conway’s rules with a refractory period: a cell that fires must rest one generation before it can fire again, the way a neuron must. That one change abolishes still lifes — nothing in this universe can stand still — so the whole grid runs with gliders, wavefronts and colliding storms indefinitely. Silverman built it while writing educational software; Toffoli and Margolus made it a standard exhibit of what one extra state buys.
PROVENANCE
- Origin
- Devised by Brian Silverman, 1984; described in Toffoli & Margolus, "Cellular Automata Machines", MIT Press, 1987
- Standing
- Public domain — a transition rule
- Constants
- The storm is deterministic per seed; it reseeds on burnout or after its run