Pendulum — the chaos of a double pendulum

A double pendulum is two rods chained together with a mass at the joint and at the tip. It's the textbook example of chaos: tiny differences in the starting angle produce wildly different paths within seconds. Pendulum lets you drop them and watch the inked tip trace beautiful, never-repeating curves.

How to play

Grab a glowing bob and swing it by hand, or drag empty space to drop a fresh pendulum — that point becomes the anchor, the drag direction sets the initial angle. Release with momentum to fling it; bobs collide elastically, kicking each other into new chaotic paths. Swing kicks every live pendulum with a fresh random impulse, Clear wipes the trail.

Why it's satisfying

A double pendulum is one of the simplest physical systems where exact prediction is impossible. The trail it leaves is mathematically beautiful — Lyapunov exponents made visible. Hard to look away.

About

Pendulum is part of Alcy, free contemplative micro-games. For more physics: Orbit, Wave, Spirograph.