Two-Dimensional Totalistic Code 52
Among the simplest two dimensional CA are the five-neighbor totalistic CA, of which there are only 64. This talk focuses on code 52.
The first thing to understand is its typical behavior. The next is its the range of behaviors, followed by its connections to other rules that give evidence for its universality.
One can think of the 5-neighbor totalistic rules, and code 52 in particular, as a gateway to the computational land of 2D CA.