A mature and stunning ray tracer, self-supported in a fully OpenSource way.
This page looks more like an image gallery
(see http://wiki.rubygarden.org/Ruby/page/show/FractalLifeEngine/LampTutorial)
The right sphere looks stretched due to curvilinear perspective. The picture is a detail of a bigger picture, with the camera aimed at the source of those arm things. Spheres nearer the center look more round.
And a few more: