Never let it be said that science has contributed nothing to art! The study of optical illusions not only gives us crazy cool images to look at, but tells us about who we are and how we function in the world. Contemplate that.
I somehow forgot to link to the 2014 Optical Illusions finalists, which is apparently a thing, but there you are. There are some pretty cool optical illusions in there.
Of course, you could just watch the new OK Go music video instead, which is one long set of optical illusions.
Business Insider has an explanation of how many of the illusions work and made us some pretty GIFs while they were at it. Go read!