If you go to DIsney's website, and look at the webpage for the Poly, then go the image of the 'lobby,' you can see a hidden Mickey quite clearly in the slate flooring! Just thought I'd pass it along!
Yes - I saw it for the 1st time on this last trip. We've been there 3 times before and never saw it. But once you see it, you realize it isn't so hidden (it's pretty big)!!