Ever heard of Anamorphoses? In short, they are pictures recognisable only from a distinctive point of view, also referred to as the spitting image of three-dimensional objects. As they can be applied in highly creative manner within photography and videography in order to trigger that certain “wow effect”, they are one of the most interesting optical illusions, the way I see it. The following video impressively shows what can be done with anamorphoses.
The illusion is perfect, were it not for the narrow depth of field, by means of which a trained eye is able to expose the trick. This can be best observed with the baseball. Instead of a horizontal stripe, a circular area closest to the camera should be sharp. The rest vanishes in background blur. The sharp horizontal stripe points to the fact that the ball is not round, but flat and tilted. Anyone who ever took photos of autofocus test charts will recognize the specific depth of field of a backwards-tilted piece of paper. 😉