It’s sometimes called “Einstein’s Riddle” because, according to legend, Einstein invented it as a child. Others say that the puzzle was actually designed by Lewis Carroll, best known as the author of Alice’s Adventures in Wonderland. (Carroll was also a logician.) Where did this brain teaser originate? We’re not really sure. Perhaps it was a 1962 issue of Life International magazine.
In any event, “Einstein’s Riddle” is a good test of your mental agility. They say that only 2% of the population can solve the problem. The TED-Ed video above will walk you through one version of the riddle. If you don’t want any assistance, you can find other versions online.
Would you like to support the mission of Open Culture? Please consider making a donation to our site. It’s hard to rely 100% on ads, and your contributions will help us continue providing the best free cultural and educational materials to learners everywhere.