# Cut Your Bagel The Mathematically Correct Way

August 6, 2015

When I interviewed mathematician Eugenia Cheng for an upcoming episode of The Sporkful podcast, she sliced a bagel along a Mobius strip.

A Mobius strip, in case you’re not familiar, is a surface with only one side. You can make one by taking a strip of paper, twisting one end halfway around, and taping it to the other end. Like this:

If you were to start drawing a line down the middle of the strip and just keep going, you’d cover all the paper and end up right back where you started, without ever flipping it over.

So Dr. Cheng sliced a bagel that way, and it was cool. But how did it make the bagel more delicious?

“Well, it’s basically completely ridiculous,” Cheng says. “And isn’t that delicious?”

Perhaps. But it occurred to me that the doctor may have stumbled upon a cure to the terrible trend plaguing bageldom. (You haven’t heard?!) Bagels are getting too big and puffy, throwing off proper ratios to cream cheese and lox. Something must be done.

So like any great academic, I built on the work of my esteemed predecessors, Dr. Cheng and Dr. George Hart, who gave us the Mathematically Correct Breakfast.

I began by drawing a Mobius strip on a bagel:

The line needs to wrap around the outside and inside of the bagel, and end up connecting to the beginning. Then slice along the line using a small, nimble knife.

When you’re done, the inside should look like an M.C. Escher staircase.

Now ready to get crazy? Slice a second Mobius strip, about a half-inch away from the first.

Spread cream cheese on all the insides, then add lox.

By creating two levels of cream cheese and lox, we’ve improved their ratios to the bagel. And by slicing along Mobius strips, we’ve created something not only delicious, but also architecturally striking.

Behold! And yes I ate it, Sharpie and all.

To see a video of Dr. Eugenia Cheng’s Mobius Bagel, check out the full version of this post, which originally appeared on Digg.

Dan Pashman is the James Beard Award-nominated creator and host of The Sporkful podcast at WNYC and the Cooking Channel web series You’re Eating It Wrong. He’s also the author of Eat More Better: How To Make Every Bite More Delicious. The Sporkful is available in iTunes, at Sporkful.com, or wherever you get your podcasts.

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