# Math Monday: Tie your bagel in a knot!

## Tie your bagel in a knot!

By George Hart for the Museum of Mathematics

Our post on how to cut a bagel into two linked halves was so popular that we thought we’d show you some more mathematical food play: how to knot a bagel. (This also works with inner tubes, but they’re very chewy.)

The bread of a bagel forms a simple loop, which mathematicians call “the unknot.” But there are two easy ways to cut a bagel into a simple overhand knot, or “trefoil” knot. Above is a what mathematicians call “the (2,3)-torus knot toasted with cream cheese.”

Another is the (3,2)-torus knot, shown here with a string following the path of the bagel, to make it clear how it’s a trefoil knot.

Detailed recipes for both of these breakfasts are shown here.

### Gareth Branwyn

Gareth Branwyn is a freelancer writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor for Boing Boing and WINK Books. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.

• David Rysdam