Double Pendulums

A year ago I watched this video about how double pendulums aren’t always chaotic.

Depending on the initial conditions they can be surprisingly non-chaotic. Even more interesting, there are little islands of stability in otherwise chaotic regions of the parameter space. I wanted more control to explore the 2D map shown in the video, so I built my own tool. It’s hosted at doublethe.fun and is open source. The core was written last year. I finally got around to adding an explanation and a major optimization thanks to Fable 5.