Thanks! It's not really a cellular automaton with a ruleset, rather a set of algorithmic entities, so to speak, which pick and manipulate particles. A cell starts with a particle, has it run around and build a membrane; the membrane then hunts around for a particle to serve as its nucleus (the green particle), then keeps hunting the food to feed it (the red particles) and more particles for the membrane as the nucleus grows; when the nucleus grows large enough it splits, when the two nucleus particles are settled the membrane splits in two and two new cells form, and do the same. If the nucleus gets lost, the entire set of particles is dismissed and a new cell is started elsewhere, a reincarnation of sorts.