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 is a freelance 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 to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.

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