TIM
A raytracer for forbidden optics
*** TIM's (now Dr TIM's) source code has moved to https://github.com/jkcuk/Dr-TIM ***
TIM is a raytracer that was originally developed to simulate optical components called METATOYs, but it has since then developed into something much more general. Amongst other things, TIM can also calculate random-dot stereograms and anaglyphs and visualise ray trajectories.