La Torre,"
an optical illusion artwork
by artist Leandro Erlich (2007)
(Click to enlarge)
I found this via the Make: Online blog, which showed his artwork Shattering Door. I've never seen any of his stuff live, but I'm sure it's better when it's experienced, just like a good magic trick. His best work is interactive, where he plays with our expectations of what we're actually seeing, and if we saw it in person, we'd know we're really seeing it because we'd be right there. His art is accessible by your eyes and body. It would make kids (and the kid part in adults) go: "Cool. That's so cool!"