How many black dots do you see?
there are no black dots its an optical illousion when you look at one corner of the image you kinda see a black dot in the center of some of the dots in the opposite corner of your eye cause your brain is lazy and doesn't really feel like translating entire images.
Try looking at plain vynil tiles on the floor... don't really focus, just stare., after awhile the lines between the tiles will begin to dissapear and reappear, maybe even change clolours




This one's pretty cool, when you look at a particular dot they run somewhere else!