# CHENG!!!!!!

This post popped into our news queue just before Christmas, and was forgotten about thanks to the seasonal good cheer. Well, it’s 2015 now, and our Nonsense Formula Disapprove-o-Matic is beeping angrily. We still can’t muster up enough enthusiasm to properly dig into this, so I’ve just tidied up the links I collected earlier on.

Eugenia Cheng (of nonsense formulas passim) has “found” the formula for the perfect doughnut, for Domino’s Pizza. Coincidentally, they’ve recently started selling doughnuts.

Actually, “formula” should be in quotes as well – the “formula” she gives is, drumroll…

$\frac{(r-2)^2}{4(r-1)}$

Note that that’s not a formula.

Apparently the best value for this ratio is “3.5 : 1”, which I reckon implies that $r \approx 1.063$. That’s $1.063$ of whatever units $r$ is measured in. This is one case where I’d particularly like to see some working out. Knowing Eugenia, she’s made up some crazy model and done variational methods on it to come up with something that’ll fit nicely in the Domino’s press kit.

Her students have picked up her habit: they made up this set of formulas for the perfect christmas tree, for Debenhams.

… which they also came up with in 2012 (although they were pipped to the post in 2013 by Kingston University’s Gordon Hunter, playing for Team Dobbies Garden Centres).

The “Christmas tree facts” box in 2014’s Christmas tree formula press release has some pretty bold claims about the amounts of baubles, tinsel and lights the tree in Trafalgar Square, London, would need. We tried to contact London City Hall to check if the figures match up, but received no reply.

In conclusion: it’s such a shame Eugenia Cheng keeps doing this. She does plenty of other stuff that’s actually worthwhile, like this introduction to higher-dimensional category theory for non-mathematicians. We invite Eugenia to get in touch, if she’d like to explain how these “formulas” concocted for advertising purposes benefit mankind.

## About the author

• #### Christian Lawson-Perfect

Mathematician, koala fan, Aperiodical editor. Usually found paddling in the North Sea, or fiddling with computers.