Uploaded March 2017 | Updated September 2026, 3 weeks ago

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Try 23andMe at 23andme.com/braincraft
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BrainCraft was created by Vanessa Hill (@nessyhill) and is brought to you by PBS Digital Studios. Talking psychology, neuroscience & why we act the way we do.

My Twitter twitter.com/nessyhill | Instagram instagram.com/nessyhill

Hosted, Animated and Produced by Vanessa Hill 🍦
Written by Teagan Wall twitter.com/TeagWall

And thank YOU for watching.

References 🗂

This riddle first appeared in Grossman, Howard (1945). Scripta Mathematica XI

TedED have a similar riddle that's beautifully animated: youtu.be/tE2dZLDJSjA