Just two days ago I watched the episode "Wie man sich täuschen kann" of Quarks und Co. (Which has a very nice Video Podcast - by the way)
They had this beautiful illusion - but in an animated form, which I have never seen before.
Well, after two hours, I had a screen-saver running and really like the results.
So, here you go too. :)
- [source:open-source/skewed-lines-illusion-screensaver browse source]