I was goofing around with various graphics tools, as is my wont... I made these some time ago, during the course of my puttering.
Here's a ray-traced, rotating Lojban logo:
http://web.meson.org/art/lojlogoanim.gif
(Hmm. Oh yeah, I forgot, the aspect ratio is bad in that one. Well, I'll fix it someday.)
Necker cubes are fun in and of themselves. I kind of like this version I made:
http://web.meson.org/art/neckercubework.gif
I also have an "impossible" cube that was actually ray-traced as though perfectly possible. Maybe I'll put it up... and people can wonder how I pulled it off! --mi'e mark.