An empty cell grows a tree with probability p. Lightning hits a tree with probability f. Fire spreads to neighbouring trees, then burns out to empty ground.
Tap to plant or ignite. The same ?seed= always gives the same run.
LITThe Drossel–Schwabl forest-fire model (1992). Every 30 steps the cell states are recounted and must total the grid, or the page throws.
AMBERCriticality is shown, not proved, on the page.