Sandpile — a live Bak–Tang–Wiesenfeld abelian sandpile that grows and avalanches forever; self-organized criticality, live in your browser.

sandpile
self‑organized criticality
grains 0 · 0:00
move to steer  ·  click to dump  ·  space to pause drag to steer  ·  tap to dump

About Sandpile

Sandpile is a live simulation of the abelian sandpile, a classic model from mathematics and physics. Grains of “sand” drop one at a time onto a grid; when a cell holds too many, it topples and spills grains to its neighbours, which can topple in turn. The result is a chain reaction — an avalanche — that ripples across the pile in intricate, self-similar patterns.

The model is better known as the Bak–Tang–Wiesenfeld sandpile, the 1987 idea that introduced self-organized criticality: systems that naturally drift toward a delicately balanced state where one added grain can trigger an avalanche of any size, from a single cell to the whole grid. The same principle is used to describe earthquakes, forest fires and market crashes. Here it runs in your browser in real time, so you can watch order and chaos trade places.

To use it, just watch the pile grow and avalanche. Reload the page to wipe it and start fresh from empty — no two runs ever look quite alike.