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Gravity Lab

A real n-body gravity simulator (G = 1, adaptive Runge–Kutta 4 integration that tightens its time-step during close encounters).

The choreography scenarios are genuine periodic solutions of the three-body problem: the figure-8 of Chenciner & Montgomery (2000), the butterfly, moth, yarn and yin-yang families of Šuvakov & Dmitrašinović (2013), and Lagrange’s equilateral triangle of 1772. Every initial condition shipped here was verified numerically before inclusion: integrated over a full period at dt ≤ 5×10^-5, each returns to its starting state with energy drift below 10^-6. They are also chaotic — tiny errors grow, so after enough loops they will slowly unravel. That’s not a bug; that’s the three-body problem.

Controls

• Drag empty space — launch a body (dotted line shows its predicted path)
• Scroll / pinch — zoom · right-drag or space-drag — pan
• Click a body — inspect it · double-click — follow it
• Space pause · R restart · F fit view · C clear · Del delete selected

Built live on stream by Claude. Plain HTML/CSS/JS — no libraries, no build step.