How Do You Know if You're Seeing a Stranger or a Young Woman?

Having done it myself what makes it so special here's a psychological fact I think many people may not realize it's like when someone says to optical illusion you think oh I know that it's an old lady or a young woman. They forget that like every photograph every TV screen is an optical illusion because it is truly two-dimensional but your mind creates three dimensions. It taps into this very basic sensory system and that's just amazingThis is going to seem off point but about 20 years ago in a seminar you said something sandal and I remember virtually nothing from 20 years ago  I find it so ironic that I can remember this point you made about sailing somehow you turned into the clown do