Thaumatrope is an optical toy in which a disk with a picture on each side is attached to 2 pieces of string. When the strings are twirled quickly between the fingers the 2 pictures appear to blend into 1 due to the persistence of vision in which human eye and brain retain a visual impression for about 1/30 of a second. Even though "Animation speed" is set to maximum (0), animated GIF is not fast enough to adequately mimic the physical thaumatrope.
