This is Phun

It's a 2D physics sandbox.

Phun is a Master of Science Thesis by Computing Science student Emil Ernerfeldt for supervisor Kenneth Bodin at VRLab, Umeå University. The solver is based on work by Claude Lacoursière.

Phun is meant to be a playground where people can be creative. It can also be used as an educational tool to learn about physics concepts such as restitution and friction.

Download it from Phun