Replicators: B3578/S23

This replicator for rule B3578/S23, was found by Dominique Giard in 1999. It replicates itself every 12 generations, on a two-dimensional 4-unit grid.

Intriguingly, the same rule has two almost-replicators, of periods 29 and 41, formed by placing two beehives end-to-end near each other. The same period 12 replicator also works in three other rules, of which B3578/S237 has the most interesting small spaceships.

Replicators -- Cellular Automata -- D. Eppstein -- UCI Inf. & Comp. Sci.