Korean Mathematician, 29, Solves 58-Year Geometry Puzzle

Dr. Baek Jin-eon was 29 when he finally solved a puzzle so simple a child could understand it, yet so difficult it defeated experts for nearly six decades.

The "moving sofa problem" asks one deceptively tricky question: What's the largest possible shape that can move around a right-angled corner in a hallway that's 1 meter wide? Austrian-Canadian mathematician Leo Moser posed this brain teaser in 1966, and it quickly became famous because anyone could grasp it without advanced training.

For years, mathematicians kept proposing bigger and better shapes. In 1968, British researcher John Hammersley designed a sofa shape measuring about 2.2074 square meters. Then in 1992, Rutgers professor Joseph Gerver created an even larger curved figure at roughly 2.2195 square meters.

Gerver's design became the leading candidate, but nobody could prove whether an even bigger shape might exist. That uncertainty gnawed at mathematicians for three more decades.

Dr. Baek, now 31 and working at the Korea Institute for Advanced Study, spent seven years closing that gap. His 119-page paper, released in late 2024, proves that Gerver's figure represents the absolute upper limit. No larger sofa shape can make that turn.

What makes his work especially impressive is the method. While earlier attempts relied heavily on computer estimates, Dr. Baek used pure logical reasoning to establish his proof.

"You keep holding on to hope, then breaking it, and moving forward by picking up ideas from the ashes," he told his institute. "For me, mathematical research is a repetition of dreaming and waking up."

Scientific American recognized his achievement among the world's top 10 mathematical breakthroughs of 2025. His paper is now under review at Annals of Mathematics, one of the most selective journals in the field.

The solution shows how persistence and creative thinking can crack problems that seem impossibly stubborn. Dr. Baek's seven-year journey proves that even questions simple enough for anyone to understand can hide depths that challenge the world's brightest minds.

His work joins a proud tradition of mathematicians who tackle problems not because they're useful in daily life, but because human curiosity demands answers. Sometimes the most beautiful breakthroughs come from asking the simplest questions and refusing to give up until we find the truth.