What is illusion?

What is illusion?

I will begin by asking, what is illusion? It’s used in rituals. Is paradox an example of illusion? Escher’s work, it seems to me, is mostly paradoxical. Oh, indeed. It is a deep, even pivotal element of illusion. Something that appears one way but is another. Escher did a lot of illusion. Stairs going up, but if you walked them you went nowhere. Well,...