Wow! Thanks JM. Those were amazing. Even after I knew what he was doing the illusion was so strong it was hard to see it as just drawn on the sidewalk. The last pictures where he shows it from another angle was cool.
Jumpmaster, hotlinking isn't permitted. Since the graphic seems quite necessary, or at least provides substantial content to your post, I uploaded the image to imageshack, and edited your link to point to the image.
Incidentally, that's a very interesting site. Thank you.
I've seen these around but like drizzle said, the one 'unveiling' it from another angle was what I've been looking for Cool stuff!!!! Excellent sense of depth and perspective (or whatever the correct terms are)