Start watching the video above (click the link) and you may not believe that it features an ordinary (albeit oversized) chessboard. The board seems to contort inwards but that’s because the corners of some of the squares are highlighted with tiny pieces of paper. Once they’re blown away, a regular pattern of parallel squares is revealed.
This video was created by Greg Ross, an illusion fanatic with his own YouTube page dedicated to the cause. He constructed the illusion after he was baffled by a similar trick. “The one I saw looked as if the black and white squares were warped and bulging outwards towards me. I had to actually use a ruler to prove to myself that they were parallel,” he says.
To re-create the brain trick, he had to figure out exactly where to place the paper dots to achieve the perception of inward distortion. Then, it took four hours to painstakingly lay out 200 hand-cut paper squares onto a custom-printed board. “Placing the squares on the pattern was one of the most tedious things I’ve ever done in my life,” says Ross. “I had to use tweezers to maneuver them and static electricity repeatedly thwarted my efforts.”
If you think you know why we perceive this illusion, let us know in the comment thread below and we’ll let you know what the experts say next week.
(If you’re wondering what the blue shape in the video is, it’s Ross’s hat. He forgot he was wearing it during filming but there was no way he was going to do a re-take.)
Source: New Scientist