optical illusions are through physical placement, not the essence of the mind twisting it, the reason illusions are there, requires a little bending, and you can see illusions online, and in books right? I highly doubt you've seen more in your real life than you have on a 2-d surface. Illusions occur, when a certain thing, for example the yellow duck illusion (what I call it anyway). You draw a duck, or anything that's supposed to be yellow (your mind sees it better), and draw a yellow square over it, when your close, it's a yellow square on a duck, and further away, it's a yellow duck. your mind molds the two images together, creating one image. Just know, that illusions can be 2d, and in that case, a camera picture isn't any different.