Skewed Lines Screen-saver
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. :)
