Odd!

[B00]

http://i40.tinypic.com/2hn0r5s.jpg

Upper block darker right?

Think again!

Hold your finger over the the join and look again :-)

(Here's the science bit- http://www.dailymail.co.uk/sciencetech/article-2521023/Dont-believe-eyes-These-blocks-SAME-shade-gray.html )

[pixie373]

I've seen that somewhere before, dt. I agree, it's really clever.

[China Doll]

Both ways for the dancer - I just look to the right for a split second and when I look back she goes in the opposite direction; I can do it if I focus but takes longer.

Cool trick!

[boingo]

DTC, Escher was a genius and is my favourite artist. I have several posters and books about him and could look at his work for hours and still find new things in them.