A row of dominoes stands on a table, each modelled as a rigid rod pivoting about its base edge. Click anywhere (or press Space) to tip the first one. Gravity's torque grows with the tilt angle — the classic unstable-pendulum equation θ″ = (3g/2h)⋅sinθ − c⋅θ′ — and when a falling domino's top edge reaches its neighbor, a fraction of its angular momentum transfers across. Widen the spacing past the domino's own height and the chain physically cannot reach the next tile: the reaction stalls mid-row, exactly as it would on a real table.