This is an extension of RectangleParticle class for APE engine.
It added angular velocity and caculates the rotation movements for a RectangleParticle when collision happens. The particle now acts like a real box.
Here is the sample:
No constraint were used in this sample, all objects are particle.

Updated on 9/23:
Rewrote the hitpoint finding method, No more sudden spinning now...
Press UP key to add more boxes to the scene. you can see it's power.

the source code is here.