@Shirley Martin: I didn't think it helped, or hurt, your chances of seeing the picture, to know what it is beforehand. I just figured if I only said "I see it!" some people might not believe me. Sorry, Shirley. Anyway, if you can see it, it just shows your brain is easily fooled, according to @Michael Kaytoo 's post.
He has one very long arm! What's weird to me is you can look around ... sides, top, bottom, corners, and the image doesn't disappear. I wonder if they have invented a camera that can add 3D effects similar to that to a picture.
In the green one, I can make out a 3D effect but I can't quite focus the picture. I think it must be because of my bifocals. With the books, I can move it around, up and down, etc. I can't do that with the computer. But I'm going to keep trying.
I checked it out without my glasses (specs) and I was able to see it. However, I had to move very near the picture Around 6 inches in distance.
I used to have no problems with these images, but since my right eye went wonky I just can't make them out.
I have no perifferal vision but I don't see a single hidden anything even tho I believe it to be there.