Physical Audio has updated PA3 Derailer to version 2.0. This update includes all new graphics, and tweaks to the audio engine.
Derailer is a physical modelling system with two basic elements. One is a metal bar that you can strike or bow, the other is a nonlinear spring connection. This allows you to join two bars together so that vibrations from one create sympathetic resonance in the other.
By connecting multiple bars you can create new instruments that have their own unique sound. Derailer uses finite-difference time-domain numerical modelling.