An expanding spiral of standing dominoes topples in a chain reaction from the center outward, then resets and loops. Real domino chains work the same way: a toppling domino releases stored gravitational potential energy and can knock over a neighbor roughly 1.5x its own size, letting cascades grow explosively—the largest real-world arrangements (e.g. Guinness-record attempts) have toppled over 4.8 million dominoes in a single chain reaction. The wave speed depends on spacing, height and friction, not on how hard the first domino was pushed. Drag to orbit, scroll to zoom.