[jaen]

What's the physics solver used here? This demonstration quickly runs into common problems associated with overly simplistic solvers/integrators where everything starts to become unstable and "vibrate" / "twitch".

[phil-martin]

It's nape-js

https://newkrok.github.io/nape-js/index.html

While the gummy geometry one is a little twitchy, but most all the other demos were very stable, much more than most other 2d solvers I've seen.