Silk is a collection of robotic UI experiments. Check out the live gallery.
To make deployment to GitHub pages easier, all the code lives in the gh-pages branch.
One technique used extensively in Silk is mathematical optimization, especially for inverse kinematics (IK). Silk's optimization code is written in C++ and uses Ceres Solver, a really nice non-linear least squares library with automatic differentiation. The C++ code is then transpiled into Javascript using Emscripten.