*Double Maths First Thing is Colin’s weekly news summary. Or autumnal, if you’re reading this after the equinox. You can sign up to receive it in your inbox on a Wednesday morning here.*

Hello! My name is Colin and I am a mathematician. It’s Wednesday morning, and it’s Double Maths First Thing.

## Shape-ology

Over on the Talking Maths In Public WhatsApp group, we’ve been looking at collapsible polyhedra, which Barney Maunder-Taylor calls Flatonic Solids. He’s not the only one, though: here’s a satisfying Instagram reel and an article by Liz Meenan in case you want to make your own.

It also reminded me that you can do cool things with pop-ups, whether or not you have the book.

## Speaking of books

Tom Briggs has been compiling suggestions of maths books that aren’t about teaching. I’m given to believe he might be making his own addition to the list in due course.

Peter Rowlett and his son have been reading Gulliver’s Travels, and found an interesting early description of something computery. A biased generator of randomness that produces plausible English? I bet the venture capitalists would be all over that.

## Sudoku

I recently had cause to revisit the Miracle Sudoku video — memorably described at the time by Ben Orlin:

You’re about to spend the next 25 minutes watching a guy solve a sudoku.

Not only that, but it’s going to be the highlight of your day.

The highlight of *my* day recently was coming across Phistomephel’s ring, which is a neat consequence of standard sudoku rules.

Tony Mann pointed me at another Cracking the Cryptic video with the same energy — the frustrations and feelings of stupidity that come with not having the answer yet, followed by the sheer joy of having worked out something clever.

Another (and significantly shorter) video plausibly worth your time is Alyssa Williams and Christian Scott at G4G discussing how to set variant sudoku.

## Joy in maths

Back to taking pleasure in maths, here’s a short interview with Talithia Williams, PhD: I loved the bit about maths appreciation, and trying to change the mindset that maths is about doing calculations to pass a test.

Another article that caught my eye this week was about climbing. Or rather, spotting an error on the climbing wall and getting it fixed. It’s interesting for several reasons, but what grabbed my attention was what I think of as x-ray vision: the power to see that something looks off, and the insistence that it be put right. That strikes me as a very mathematical thing. (And, speaking for myself, possibly an autistic thing. Drives me MAD when people don’t care about breaking the rules, I tell you.)

## For your listening pleasure

This week, I have mostly been listening to:

- Tim Harford’s Cautionary Tales
- Bec Hill and Matt Parker’s A Problem Squared
- Evelyn J Lamb and Kevin Knudson’s My Favorite Theorem
- Katie Steckles and Peter Rowlett’s Mathematical Objects — I understand that series 8 is imminent.

I’ve not yet picked up the TMiP podcast, but we all should. And Sam Hansen would give me endless, deserved grief if I didn’t mention Relatively Prime.

## The week ahead

Thanks to September ending on a Monday, the monthly MathsJam meet-up is coming around distressingly quickly — those that meet on the traditional penultimate Tuesday will do so on September 17th. You can find your local MathsJam here — I’ll be at the Weymouth one.

Also, if you’re planning to go to Big MathsJam in November, early-bird pricing ends on Sunday.

There’s a Finite Group livestream on Friday, September 13th at 9pm BST — Katie and Ayliean are putting the ‘fun’ into ‘fundamental theorems’, it says here.

That’s all for this week! If there’s something I should know about, you can find me on Mathstodon as @icecolbeveridge, or at my personal website.

Until next time,

C