I recently took part in the Phat Quarter swap on the theme "Blinded by science". My swapee was Mr X Stitch himself, so no pressure there! I liked the idea of being blinded by science - your eyes seeing one thing but your brain receieving it another way. So I thought I'd have a bash at an optical illusion - I've not seen this done before.
The idea is that the lines of squares move or bulge diagonally. If you
let your eyes unfocus slightly, or look slightly away from the piece it
works best. It works better in real life than as a photo of an embroidery on the