Don't Trust Your Lying Eyes

If you're interested in optical illusions head over here, where they have the finalists from the "Best Visual Illusion Of The Year Award".

The picture above shows the winner, by Frederick Kingdom, Ali Yoonessi and Elena Gheorghiu, its incredibly simple, both pictures are identical (apart from a slight offset due to some dodgy photoshopping I guess) but due to to the way the brain interprets objects receding into the distance it creates the impression that the one on the right is at a greater angle than the one on the left. For a more thorough explanation see here. My head hurts now.