What's special about this simulation is that the entire code fits on one page, including linear algebra library: https://github.com/aguaviva/Physics/blob/master/RigidBodyCha...

I've been trying to understand js physics simulation for many years, and this is the first demo that I find understandable. Amazing work!

Fantastic, in fact I wrote because I had been trying to understand physics engines four a long time and it was super hard to follow the papers. I wrote it four learning my self and published it to help others not go through my frustration :)