Fire

Forest-fire cellular automata come out of the same tradition as percolation demos and the classic NetLogo Fire model: a simple grid, a random stand of trees, and a flame front that reveals how density controls connectedness.

Here every patch is either empty, tree, burning, or burned. Setup plants trees according to the density slider and lights the left edge; each staged tick burns current flames out while any tree with a burning four-neighbor catches fire, then the run stops when no burning patches remain.