 Notwithstanding the computational interest of one-dimensional CA, philosophical issues have been discussed more often in connection with two-dimensional CA. The first CA, von Neumann’s self-reproducing automaton, inhabited a two-dimensional grid. Besides, two-dimensional CA are suitable for representing many physical, biological, and even human phenomena, ranging from the dynamics of perfect gases to the movements of birds in a storm and soldiers on a battlefield. The most common configurations have either square or hexagonal cells, given their translational and rotational symmetries. Moving to two dimensions, of course, also expands the possibly interesting combinations of rules and neighborhoods. As for the latter, the two most common options in a grid of squares are the von Neumann neighborhood, where each cell interacts only with its four horizontal and vertical adjacent mates, and the Moore neighborhood, comprising all the eight immediately adjacent cells.