help - animation of an unpossible 3D object

[va!n]

some month ago i saw somewhere on the web a site whit some unpossible 3d objects like this one: http://www.3d-meier.de/Galerie/Escher/Bild1.gif

while browsing i found two very cool animated rotated unpossible objects. as fair as i remember, they rotated like a clock and there was added a jumping ball to the object... i have spend hours to refind this animated GIFs (they has been GIFs!) but i cant find anything

If someone of you can help to find this great animated objects, it would be really very very great! (the objets are a bit more complex as the one in the topic link)... many thanks in advance!

[DarkDragon]

I have seen them, too(They have been posted somewhere in the PB forums) but I can't find them again.

[Michael Vogel]

Hmm...

my old link collection for math stuff seems to be to old, nearly no links works anymore.

Some movies (no gifs) are here: ttp://www.cs.technion.ac.il/~gershon/EscherForReal/

But most links did not work anymore - especially the funny work of a japanese who did nice paper models of escher stuff...

[va!n]

nobody an idea of the url? :roll:

@DarkDragon:
do you remember where you saw it? engl/german forum or somewhere else?