A winding line of dominoes topples one after another along a curved path, each one converting the gravitational potential energy of its own upright mass into rotational energy that shoves the next in line. A falling domino can topple a domino up to about 1.5 times its own height, which is why a chain of steadily larger dominoes can, in principle, knock over something roughly 1.5 billion times bigger after only about 29 doubling steps. The toppling wave itself travels fastest when dominoes are spaced about 1-1.5 times their width apart, producing a wave speed around 0.5-1 m/s for standard-sized dominoes - too close and they jam, too far and the chain breaks. The current Guinness World Record for a single chain-reaction event involved over 4.8 million dominoes toppled in sequence. Adjust the sliders below to see how spacing, fall speed, and gravity change the wave as it races along the curve.