HRay - Raytracing in Haskell
HRay is a raytracer written in Haskell by Kenneth Hoste for his thesis. He added a GUI for his program using Gtk2Hs. See his project website for lots of other pretty images. The code is now available, since the thesis has been presented.
HRay also runs on Windows and nicely shows off the Windows native look supported by Gtk+. By default, since Gtk+ 2.6, the theme follows the Windows theme, so everything “just works” whatever theme you use:
Of course if you can’t stand the various WindowsXP themes, Gtk+ programs will work just as well using the “classic” theme: