Species sit on a ring, each with a fitness in [0, 1]. Every step the least-fit species and its two neighbours are replaced with random fitnesses.
Tap the ring to knock out a cluster of species. The same ?seed= always gives the same run.
LITThe Bak–Sneppen model (1993), fc ≈ 0.667. Every 30 steps the fitnesses must lie in [0, 1) and the minimum must be the true minimum, or the page throws.
WALLA toy of self-organised criticality, not a model of the fossil record.