Felice Varini is a Swiss artist who is one of the undisputed specialists in anamorphosis. Anamorphosis is the art of creating the illusion of a flat geometrical shape superimposed over a three dimensional object. Viewed from the correct perspective, it will seem as if these shapes are floating in mid-air. Step away from the perfect spot and the illusion crumbles, all the viewer would see are fragmented shapes. Varini has been doing this sort of mind boggling art for the last thirty-some years.
Check out his website.