Optical illusion 27 Wednesday Apr 2011 Posted by skadhu in Uncategorized ≈ Comments Off When I took this picture it was perfectly obvious to me what I was looking at—pebbles sitting on the sand, rivulets cutting into it. But now when I look at it I see pebbles sunken in sand, and raised lines running across it. What do you see? About these ads Like this:Like Loading...