### New Twist on Sofa Problem That Stumped Mathematicians and Furniture Movers

*Hobby 3-D Printing Leads to New Insights into Moving Sofa Problem*

*Hobby 3-D Printing Leads to New Insights into Moving Sofa Problem*

*By Becky Oskin*

Most of us have struggled with the mathematical puzzle known as the “moving sofa problem.” It poses a deceptively simple question: What is the largest sofa that can pivot around an L-shaped hallway corner?

A mover will tell you to just stand the sofa on end. But imagine the sofa is impossible to lift, squish or tilt. Although it still seems easy to solve, the moving sofa problem has stymied math sleuths for more than 50 years. That’s because the challenge for mathematicians is both finding the largest sofa and *proving* it to be the largest. Without a proof, it’s always possible someone will come along with a better solution.

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