Ok. So I found this photo of an iPad. When I first saw it I just couldn't get my brain to see the edge correctly. I saw an edge that dented in and then out. Hard to explain. Like instead of being round-convex, it was round-concave. Take a look. Do you see an iPad Optical illusion? Do you see the iPad with a convex (rounded out) edge or an iPad with a concave (rounded in) edge?
from Andrew Brett Watson.com