Domino Rally is a free online sandbox game where you place rows of dominoes on a dark canvas and then topple them to watch a satisfying chain reaction cascade across your creation. Click to place individual dominoes, or hold and drag to draw smooth flowing lines. Special pieces like splitters, spinners, and bridges let you create complex multi-path rally tracks. Two modes let you either build freely in Sandbox or solve 20 increasingly tricky Challenge levels where you must connect a start zone to a goal using a limited number of pieces.
Each domino you place automatically orients itself perpendicular to the direction you're moving, creating naturally smooth curves and turns. When you hit the Topple button (or press Space), the first domino begins to fall with realistic physics — its tip sweeps forward and triggers the next domino in the chain. The timing between hits is calculated from the actual distance between each piece, so tightly-packed dominoes cascade faster while wider gaps create dramatic pauses. A rainbow of color washes along the falling wave as each piece lights up, and the Web Audio engine generates a satisfying rapid-fire clicking sound that builds as the chain accelerates. The camera automatically follows the wave so you never miss a single fall.
A domino chain reaction works by converting the potential energy stored in each standing domino into kinetic energy when it falls. Each falling domino transfers its momentum to the next one, creating a cascading wave of topples. The timing depends on the spacing — closer dominoes transfer energy faster, while wider gaps slow the wave. A single domino can actually topple a domino roughly 1.5x its own size, meaning chain reactions can amplify in power as they go.
The world record for most dominoes toppled in a single chain reaction is over 4.5 million dominoes, set at the Domino Day event in the Netherlands. Professional domino artists spend weeks or months meticulously placing each piece by hand, often building elaborate scenes with colored tiles. Records are also kept for the longest domino chain by distance, the tallest domino tower, and the most complex split-path design.
To make a domino turn, gradually angle each domino so the line curves around a corner — in this game, that happens automatically as you drag. For splits, use the Splitter piece (key 2) which, when it falls, triggers dominoes on multiple sides simultaneously, creating two or more parallel chain reactions running at the same time. Spinners (key 3) send a radial pulse outward to trigger any nearby dominoes in all directions at once.
If you enjoyed this, try: Chain Reaction · Gravity Playground · Plinko · Falling Sand
Last updated: March 2026 · whatifs.fun — Free interactive games, experiments & simulations