That's a neat optical illusion!
Do you see the same thing I see? When I move my head towards the screen, the inner circle turns counter-clockwise and the outer circle turns clockwise. When I move my head away from the screen, the directions reverse. But if I look directly at the diamonds and move my head, it doesn't turn.
It's interesting how the shadow effect affects our depth perception on those diamond shapes. The diamonds near the top of the circles appear to be raised, and the bottom ones appear to be depressed. Somewhere on the sides, there's a transition point where the mind switches its perception from raised to depressed, but as I keep staring at it, that transition point keeps changing. If I turn my head 90 degrees, then whichever side of the circle which is now my "top" looks raised and the "bottom" looks depressed.