Focus on the dot in the center, move your head toward the screen and away from it. The circles seem to move.
Do you see gray areas in between the squares? Where did they come from?
You should see a man's face and also a word...

Hint: Tilt your head to the right, the world begins with 'L'
Are the purple lines straight or bent?
Is this possible?
Take a look at the following picture... it is not animated! Your eyes are making it move. To test this, stare at one spot for a couple seconds and everything will stop moving. Or look at the black center of each circle and it will stop moving. But move your eyes to the next black center and the previous will move after you take your eyes away from it. (too cool)