This was a quick project developed for the Tools & Middleware course (MScCGE at Goldsmiths, University of London), thought as a demo of the Bullet Physics engine.
The application shows a scene with physically-based bridges, constructed with the two main types of constraints in the Bullet SDK (hinges and springs).
Each type of constraint has a different set of parameters that can be tweaked, and so both types of bridges behave in a slightly different way.