This work of work of art, according to Neatoramanaut chriskayTO, can be found in a subway station in Toronto. Examined from the correct angle, it looks like a staircase.
I used to ride the Toronto subway a lot. Unfortunately an artwork that makes you think, "Huh, it's a pocketwatch" from one angle looks like an awful mess from every other angle.
Yeah, Andrew Hillman posted the photo on his blog, but he didn't actually take credit for it, and it's clearly the same photo that's been circulating on the internet for some time now.
Still neat though ;)