Optical Illusions (science / brain and senses)

Optical Illusions are soooooooo cool! They are very amazing and I would love to know how to do them.

They are images that trick your eyes and brain but if you study them, youwill see they are not possible or that they are hiding more that what you see at first.

Here are some common ones:

Are the circles moving or NOT!

A young girl or and old lady

This is the most beautiful one - Ref: http://www.newopticalillusions.com/illusions/anamorphism/

There are LOADS of them so check some of these out!

http://www.optillusions.com

http://www.google.co.uk/images?q=optical+illusions&um=1&ie=UTF-8&source=univ&ei=DAKKTJ2fBM-TjAe_rJ2DBg&sa=X&oi=image_result_group&ct=title&resnum=1&ved=0CCgQsAQwAA&biw=1280&bih=707

http://www.childrensuniversity.manchester.ac.uk/interactives/science/brainandsenses/