Replicators: B01357/S0123

B01357/S0123 has a period-six 2c/3 replicator, consisting of a block of two cells:

B01357/S0123 2c/6 replicator

Three parallel tracks of these replicators can interact to form an 8c/24 spaceship:

B01357/S0123 8c/24 spaceship

More curiously, three perpendicular tracks can also form a spaceship, again moving at speed c/3 but with period 12. The replicators from the middle track stop the backwards replication of the other two tracks, destroying themselves in the process, but are reformed from the resulting debris.

B01357/S0123 4c/12 spaceship

With random initial conditions, this rule fills space with a chaotic pattern of interacting replicators. If the initial density of live cells is approximately 48%, the pattern also features large regions of opposite phases (live replicators on dead backgrounds in even generations, or vice versa) with slowly annealing region boundaries. For densities away from this critical value, one phase or the other eventually takes over the whole space.

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