When Physics Solves a Puzzling Loop A recent study published in the Proceedings of the National Academy of Sciences has finally found an answer to the reverse sprinkler problem, a puzzle first popularized by physicist Richard Feynman in his 1985 book Surely You're Joking, Mr.
Feynman.
Researchers at New York University's Courant Institute conducted experiments with various designs of "silly sprinklers," those whimsical lawn ornaments that create intricate patterns with water jets, and discovered that their solution applies not just to Feynman's reverse sprinkler puzzle but also to a broader theory in fluid dynamics.