In B0136/S123, a 3x2 block forms a 9c/30 replicator:
With random initial conditions, this rule quickly settles down to large regions of live cells on even generations and dead cells on odd generations, or vice versa, with only a sparse scattering of oscillators and replicators within each region. With an initial density of approximately 45% live cells, the regions of both phases are equally balanced and have gradually annealing phase boundaries; for other densities one phase or the other eventually takes over the whole space. However, the chaotic phase boundaries occasionally create new replicators which grow and interact to eventually fill space with a dense chaotic pattern in place of its initial stability.
Replicators -- Cellular Automata -- D. Eppstein -- UCI Inf. & Comp. Sci.