Cool Spiral Optical Illusion

Here is another spiral illusion - this time in Snail-o-vision! Interesting fact about this optical illusion, is that when people encounter it for the first time, based on their previous experience with illusions, they presume it has something to do with perpetual motion. At least that is what I presumed. I thought the only illusion happening here is �seemingly moving� spiral painted on our little snail�s shell, and not the best example of that type at all! If that was it, I wouldn�t be much excited, and would probably forward this photo directly to my recycle bin. And A Cool Optical Illusion video But then I read the email that was companion to this submission. It said something like: �Is the snail shell really a spiral�? I looked at the shell more closely, The spiral is actually composed of many concentric circles. Very good!