 At time step 250 (not shown in  Fig. 5),  the grey areas disappear and all cells end up white, i.e., the classification made by the automaton is correct. A high-level description of what is going on would have it that the white, black and grey regions are “expanding”, “contracting”, “moving”, these being nonlinear effects of the low-level working of the cells computing their local states, and by so doing manage to carry signals along the lattice. But how are we to explain the emergent computation CA of this kind perform via such nonlinear dynamics? Building on previous works on computation theory applied to CA (Hanson &amp; Crutchfield 1992; Crutchfield &amp; Hanson 1993), Mitchell and Crutchfield filtered out from the original diagram what they call “domains”, i.e., dynamically homogeneous spatial regions (Crutchfield &amp; Mitchell 1995: 10745): 