Alongside cellular automata, you can also simulate a sand dune model using reaction-diffusion systems such as a modified Belousov-Zhabotinsky model. The 'reacti

Alongside cellular automata, you can also simulate a sand dune model using reaction-diffusion systems such as a modified Belousov-Zhabotinsky model. The 'reaction' here is the aeolian process of wind being funneled against piles of sand. 'Communicate' is perhaps a stretch, really what's happening is that in a grid simulation, all the computation is done in parallel from a point to its neighborhoods, with each step simulating exchange of information to alter the state of each cell. For most simple models, this merely entails flipping the state between active and dormant (so 0 and 1) for each cell. And most models only consider adjacent neighborhoods (such as von Neumann or Moore). That is to say, you can observe complex global behavior based on simple local patterns.