Special Go board

A special Go board. Can you see the white and the black stones? But wait - what is white, what is black here? :)

That hurts! :) LoP

This may happen to you if you play too much GO...(I've found the above picture on a website about visual illusions.) MarkD

Technical details:

This is called a Scintillating grid illusion and interesting if the lines would not be straight but wobbely the illussion would not occur

a bigger example