I had this illusion on my computer for some time now, but never took time to understand it. Thought it doesn’t do much… Boy, was I wrong! When you concentrate on the center circle, not only does it appear leviating in it’s 3D enviroment, the main illusion jumps at you when you start moving your head back and forth. Moving away from your screen, and then slightly comming back produces white areas of the circle grow, thus circle takes role of a magnifying glass! Another simmilar illusion can be found inside this post (click on the title of the post).