My toddler's train track is freaking me out right now. What is going on here?! pic.twitter.com/9o8bVWF5KO— marc blank-settle (@MarcSettle) April 6, 2016
BBC Academy trainer Marc Blank-Settle was tidying up his toddler’s toys when he stumbled across a mind-bending phenomenon that left him scratching his head.
The two pieces of wooden train track set, which looks like an innocent plaything but has since left thousands across the world confused and frazzled, appear different in size. However, when placed upon one another, the two pieces appear completely aligned.
“I was tidying up my son's train track... again, as I do every evening,” the journalist told Mashable. “But this time, I stacked one piece on another (rather than just flinging them all in a box) and lined them up exactly. I then (for some reason, no idea why) took the top one off again and placed it on the table below the other one and *blam* — then I saw it.”
Black-Settle shared the baffling optical illusion on Twitter, on Wednesday, where it racked up thousands of retweets and replies from viewers who could not wrap their head around the phenomenon.
People even began measuring their own kids’ toys in hopes of understanding it better:
Like every other optical illusion, the mystery of reasoning behind this accidental discovery lies in science — or the science of shapes, to be precise.
As explained by American psychologist Joseph Jastrow in 1882, if you line up two identical shapes with four sides (two curved and two straight) and put the straight edges in a line, one will appear larger than the other. Known as Jastrow illusion, essentially it is all about how our brain perceives an image.