Sandro del-Prete started his work as an experiment: he started to draw scenes or objects that could be seen from different points and from that moment a new kind of illusion was created. In conclusion most of his visual optical illusions can be perceived in two different ways. I think that so far we’ve understood how the theory of perspective works like, so today I am going to give you one last hint about this theory, the others maybe in a few days.
What to see?
You can see in the middle of the picture a crusader standing on a horse. The way the pieces are combined leaves us the impression that they’re a perfect match even if all the pieces seem slanted to the left, right, forward or backwards.
How it works?
For this picture and all the others to be perceived correctly it has to be seen from the center of it. If we keep track of the distance we have to say that any parallel pair of right angles in the picture defines the correct viewing distance, by determinate two orthogonal vanishing points.
To be more precise the plane of the picture to be seen in the way it was designed it has to be viewed at the angle of slant for which the perspective was created.
Enjoy and try to analyze these illusions properly.