 Consider, however, a spatialized Prisoner’s Dilemma in the form of cellular automata, easily run and analyzed on a computer. Cells are assigned one of these eight strategies at random, play an iterated game locally with their eight immediate neighbors in the array, and then adopt the strategy of that neighbor (if any) that achieves a higher total score. In this case, with the same 8 strategies, occupation of the array starts with a dominance by All Defect, but clusters of Tit for Tat grow to dominate the space  (Figure 16).  An interactive simulation in which one can choose which competing reactive strategies play in a spatialized array is available in the Other Internet Resources section below.