The moving sofa math problem: still unsolved 50 years later
by Andrea James from on (#26YTW)
https://www.youtube.com/watch?v=n5bMD3_JlFY
Ever try to move a sofa down a hallway that has a corner? The underlying math behind it inspired a math problem that's been a puzzler since 1966. Gerver's Sofa above shows the parameters: a U-shaped sofa moving around a 90-degree corner in an even-width hallway. Gerver's got the record so far, and it is likely the optimal sofa. (more")