If you have kids at home, you probably have some kind of children's train tracks there too. But did you ever look closely at them?
Dad Marc Blank-Settle did, and discovered something that blew his mind: two track parts that stacked directly on top of one another ... looked like they were totally different lengths when set next to each other!
(Warning: loud music when playing tweet video.)
Say what? How is that possible?
"I did it again and again, for my own curiosity," Blank-Settle told Mashable. "But each time the piece was placed on top of the other one, it was the same size precisely — but bigger when it was placed underneath the other one. Which fried my brain."
That confusion has resonated around the internet, with thousands of retweets and likes on Twitter. But Blank-Settle didn't go off the rails: He did a little digging and discovered that he's not the first person to notice this anomaly. In fact, it even has a name: the Jastrow illusion.
Psychologist Dr. Joseph Jastrow discovered the optical illusion in 1882. It has to do with the arcs of the items; if one lines up the lower edges of each left corner, it becomes clearer that the tracks are actually the same size.
And if Jastrow's name rings a bell, it should: He's the man who also introduced us to the confounding "is it a duck or is it a rabbit" image that blew up the internet in February.
Joseph Jastrow died back in 1944, but it seems like 2016 is his year. And that's no illusion!
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