Harmony — free browser game

Harmony is a precision-timing game built around three pendulums swinging at slightly different frequencies. Each pendulum hangs from a pivot at the top of the canvas and oscillates on its own track. A faint vertical band runs down from each pivot — that is the 'lock zone' for that pendulum, sized to match the judge's actual tolerance. When you think all three bobs are inside their own bands at the same instant, you press Space (or tap the on-screen button on mobile). If all three really are inside, you score +1, get a green flash and a brief freeze, then the game re-rolls the frequencies and starts a new round. If even one bob is outside its band, you take a miss and the bands flash red. Five misses end the run. Every three successful locks the level steps up: the frequencies spread further apart, so the simultaneous zero-crossing windows get rarer. Tips: (1) Lock onto the slowest pendulum as your reference — it stays near vertical the longest. (2) When the two faster bobs are clearly inside, wait for the slow one. (3) Spamming Space is punished; better to skip a window than burn an early miss. Your best score is saved locally.