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.

This question was first published by Leo Moser in 1966. The animation above, made by Claudio Rocchini, shows one attempt to solve this problem. It’s called the Hammersley sofa, since it was discovered by John Michael Hammersley in 1968... But it’s not the best known solution! In 1992, Joseph Gerver found a shape of area [...] that fits around the bend in the hallway. Basically Gerver rounded off some of the corners of Hammersley’s sofa. The resulting shape has a boundary consisting of 3 straight line segments and 15 curved segments.

AMS has a good detailed illustration of the Gerver Sofa, too.

I enjoyed learning about statistics, probability, zero, infinity, number sequences, and more in this heavily illustrated kids’ book called How to Be a Math Genius, by Mike Goldsmith. But would my then-11-year daughter like it as much? I handed it to her after school and she become absorbed in it until called for dinner. She […]

The astonishingly prolific author/scientist Clifford Pickover is a math enthusiast with a talent for ferreting out fascinating anecdotes about math, and writing them in a way that inspires wonder. Accompanied by beautiful illustrations, Pickover’s The Math Book about cicada-generated prime numbers, magic squares, the Golden Mean, Penrose Tiles, Xeno’s Paradox, and the butterfly effect just […]

YouTuber 3Blue1Brown has started a video series called “lockdown math.” In his latest episode he goes over the fundamentals of trigonometry in a way that is accessible and enjoyable.

Even in horrible economic times, a few simple rules hold unshakably true. And one of those rules is that if you possess an in-demand skill, you’ll always find work — and often, at a top market salary, to boot. If you understand Big Data and how to find order from the chaos of massive stockpiles […]

We live in a disposable era. If you can’t fix a broken item with a wrap of duct tape, there’s a very strong likelihood that its next destination is the trashcan. However, that probably leads to a trigger-finger death sentence for many household items that could be saved with just a bit more ingenuity. Before […]

Right tool for the right job. You probably heard a parent or grandparent say it at least once at some point. And it’s true in so many cases. If you spot a small tear in your living room curtains or near to hem a pair of pants, you can always use the good old fashioned […]