Soft body physics
Dough is a particle-based physics engine which can realistically simulate soft materials like dough, foam, and liquid.
It can handle over 4000 particles, and parameters can be adjusted for emulation of different kinds of materials.
I originally made Dough in the summer of 2012.
The data structure of Dough was revamped from Curtain's to be more cache-friendly to better handle the frequent destroying and rebuilding of links.
You can see Dough's source and try it out for yourself on OpenProcessing.