Box2D is a physics engine written in C++ by Erin Catto:
Box2D Lite is a simplified version that he posted to his blog once upon a time.
I’ve ported Box2D Lite to Ikarus. Here it is running the pyramid demo:
That’s a screenshot of the very first successful run. 🙂
Of course, I’ll be happy to release the code once the performance is cranked a bit.