The forest-fire model is a two-dimensional cellular automaton, where a cell is either empty, has a tree, or is on fire. A cell on fire turns into an empty cell in the next time step. Fires spread to all adjacent cells with trees in them. An empty cell will grow a tree with some probability (p(grow new tree) in the applet). A tree cell will catch on fire with some probability (p(lightning strike) in the applet).
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