You analyze what is there - specific lines, colors, proportions, etc - to see if what they think they see makes sense.
For instance, I asked what angle the ankle would have to be at, in order for the yellow part to be Fuddy’s shoe.
No response, except some who raged off in a huff or called me crazy for asking somebody to demonstrate their own body at the required angles.
It all looks like a vague, blurry mess to me. Which means I could see whatever I wish to see in it. As you apparently have.