The area above displays a 'sandpile' cellular automata. A cellular automata is an array of cells that change colors based on a set of rules.
For sandpile automata, there are two rules: First, there is 'sand' pouring into one (or more) of the cells. The second rule is that once a cell fills up with sand, the sand pours out eavenly into the cell's neighbors. A cell is full if the amount of sand in it is greater than the number of cells surrounding it. The amount of sand in a cell determines its color. From these simple rules emerges a constantly changing cascading pattern.
