EDIT: If you click in place at the bottom you can create some interesting "solids". And after a few they start fighting it out.

EDIT: A cool effect is to make a "solid" with one or more open shapes attached. They go springy spinner ballistic berserk.

When you fill up the space in 2D & wireframe modes, their rad moves look like living geometrica bacteriosa. In 3D & wireframe they look like they are ... well, doing things.

Also, you can hang them from the roof. Give them legs and arms.

If you create a couple layers of loosly connected shapes across the bottom, it acts like a powered trampoline.

Way too fun. This needs to be the next big casual gaming brand after Angry Birds. I want to solve problems with them. Shoot at them. Shoot them. A two-player shoot out would be hilarious. Definitely drop things on them.

& drop them outside the frame.

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.