Double Pendulum

Set a pendulum swinging, and it follows a rhythm you can predict. Attach a second pendulum to the end of the first, and everything changes. Double Pendulum lets you launch that linked system and watch it trace wild, unpredictable arcs across the screen — the kind of motion that looks almost intentional until it suddenly isn't. That sensitivity to starting conditions is real chaos theory, not a visual trick.

As the arms swing, a color-fading trail builds behind them, turning the physics into something genuinely worth staring at. You can reset with a new starting angle anytime, and no two runs look alike even when you try to repeat yourself. It fits naturally in the interactive simulations category alongside tools that make abstract science tangible. Magnetic Pendulum covers similar ground if you want to see how fixed attractors shape a swinging arm rather than pure chaos.

This one runs best on a larger screen — the trail accumulates over a wide area, and on a small display the older segments get clipped before the full pattern has room to develop.