"George Shirley" > wrote in message
...

> Concentrate James, concentrate. We used this illusion in some pysch
> classes way yonder long ago when I was going to college. Been around a
> long time if you look at the first date of use. It's easier for me as I
> dislike duck but love rabbit.

My psychology textbook had a neat illusion that was two photos of Madonna.
One normal and the other one was upside down. The upside down one had been
photoshopped so that her eyes and mouth were turned upside down. You
couldn't tell that was the case until you turned the book upside down.
Pretty neat.