board · 520 × 520grid · on
This is Conway's Life retold as a pet model. It exists to show that the same cellular automaton can be authored as one mobile-agent breed per grid coordinate, not only as patch state.
Setup creates a cells breed with one pet on every patch. Each pet counts live neighbor pets around its own coordinate, writes a binary next state with the standard birth and survival rule, and commits that state in a staged phase. The visible fade between alive and dead is handled by style transitions, keeping the simulation state itself simple.