∀x . what does the x say? https://en.wikipedia.org/wiki/List_of_animal_sounds

A lovely new video from @henryseg: https://youtu.be/NEJZlGuWGV8 Stunning photography, as well as a fascinating mechanism.

RE: https://mathstodon.xyz/@robinhouston/115763319086921540 The more I think about it, the more I want to call them ‘Triangle Cubes’. It's a striking oxymoron, and ‘disphenoids’ and even ‘tetrahedra’ are both intimidating and imprecise. How much do you hate it?

I don't think this relation symbol is in Unicode.

At last I have achieved my ambition of making all the stellations of the rhombic dodecahedron from my blocks

If anyone who has a 3D printer wants to play with the tetrahedral building blocks I’ve been having so much fun with, I’ve published a 3D model of the version I was playing with last month at https://makerworld.com/en/models/2142956-tetragonal-disphenoid-tetrahedral-building-blocks#profileId-2321371

You wanna hear about a silly mistake? I hadn't realised these pieces are chiral, until I tried to make a model that (I quickly realised) needs both versions. (So there are *three* different ways to make these with two blank faces, rather than two as I had […] [Original post on mathstodon.xyz]

It seems that Bridges have some overzealous security software running on their website.

I just heard about a cool theorem of Oded Schramm called the monster packing theorem, and I am not surprised to see that @11011110 wrote a very nice blog post about it in 2014: https://11011110.github.io/blog/2014/02/23/schramms-monster-packing.html

This is the optimal way to distribute software. I wish it were more common!

Many of my favourite paper titles naturally invite the response: ‘Your scientists were so preoccupied with whether they could, they didn't stop to think if they should.’

If you are a Mathematica guru, I would appreciate some help: https://mathematica.stackexchange.com/q/318281/89711

The mysterious network problem that cost me most of yesterday turns out to have been caused by someone helpfully plugging in a network cable that wasn't meant to be plugged in. This is the second time I've found a tricky network problem to have such a cause. I think there's some sort of […]

File system corruption on the internal SSD of my MacBook. That's a blast from the past! It apparently happened after I tried to back up to a new external SSD which seems to have hardware or firmware problems. Is it plausible that a faulty external drive could cause corruption of the internal? I […]

I really like what 2swap is doing on YouTube. Maths videos with interesting sound design! (And good animated graphics too, but that's less of a novelty.) https://youtu.be/9HIy5dJE-zQ

A fun new video from a fun series on polyhedra: this one on the echidnahedron. https://youtu.be/M04tmGlExnI

I enojyed @standupmaths playing Paul to tom7’s Jesus, as it were. https://www.youtube.com/watch?v=eeVaUNPxXy8

RE: https://infosec.exchange/@rebane2001/115661669658436967 It's not every day you see a new vulnerability *class*. Impressive and fascinating work!

RE: https://mathstodon.xyz/@OscarCunningham/115655819981333896 A nice explanation of why, if you type some number less than 1 into a calculator and mash the square root button repeatedly, the result stabilises at slightly less than 1.

This must be one of the the most unhinged workplaces in science, ever. In 1966, Fowler asked how air moves through a centrifugal compressor. To answer this question, he put a guy holding a camera on a spinning chair in the middle of a huge turbine wheel spinning […] [Original post on chaos.social]

A language I had never heard of till just now turns out to be the origin of the words tapir, toucan, coati, capybara, jaguar and tapioca. https://en.wikipedia.org/wiki/Tupi_language

I would not have guessed this was possible! Vladan Majerech has found a one-dimensional spaceship in the Game of Life: a pattern just one cell high and 3,707,300,605 cells wide that, after 133,076,755,768 generations (during which it is not confined to the one-dimensional line, of course) […]

My version of a very nice, rather difficult, dissection puzzle – of unknown origin – that has been circulating for many years, but of which I learnt only recently. (Please at least spoiler-tag any hints, clues, guesses, context, speculation, or attempted […] [Original post on mathstodon.xyz]

How many triangles?

A chocolate orange without the orange? Whatever next‽

Someone at MathsJam – I didn’t catch who, and I can’t seem to find out online – ran a cool competition where you had to find the largest connected polyomino that has no five squares collinear. https://polycomp.pythonanywhere.com/app/event/mjg25poly The best […] [Original post on mathstodon.xyz]

I had a cool experience on Saturday night at MathsJam. Mike Borcherds had brought a pile of 3D-printed puzzles for people to play with; and I recognised one of the puzzles in the pile as one I had designed! (It was this one […]

From 2022, but new to me: Computational Design of High-level Interlocking Puzzles https://sutd-cgl.github.io/supp/Publication/projects/2022-SIGGRAPH-High-LevelPuzzle/index.html

I am witnessing the birth of a rhombic dodecahedron

Tim Berners-Lee on Desert Island Discs: — The Bible: could I choose a different religious book if I want to? — You can, yeah. Would you like to? — Oh, I'll take the Bible, but I wanted to make sure I had the right to choose. Never change, Sir Tim.

A shockingly short list. https://commons.wikimedia.org/wiki/Category:Hexagonal_buildings_in_England

Thanks to a commenter on the Lean Zulip, the other day I learned of "safe" functions, which are an abstraction of what it means to have a function on tuples of binary strings (outputting a binary string) that is polynomial-time computable. See for example section 4.1 of […]

Continuing their long tradition of being the most geometrically adventurous chocolate manufacturer, Toblerone have a range of enneahedral chocolates.

RE: https://mathstodon.xyz/@robinhouston/115519011082424073 At least one person read this as an excoriating criticism. It wasn't meant to be! I enjoyed the interview a lot!

There's a new episode of the Mathematical Objects podcast where the hosts (@stecks and @peterrowlett) interview Grant Sanderson (3blue1brown) about his love of wooden puzzles – specifically the three pictured below.

A surprising tessellation

I can't believe I didn't know this fact before today - it seems so fundamental. If you have a real symmetric matrix A, and pick some unit vector x, then x.Ax (the Rayleigh quotient) is bounded by the smallest and largest eigenvalues. So what happens if I pick […] [Original post on mathstodon.xyz]

I *thought* it was weird that we hadn’t heard more from mathematicians using AlphaEvolve. It turns out they were just biding their time to drop an 80-page mega-paper describing its use on 67 different problems(!) https://arxiv.org/abs/2511.02864

Need to pack a lot of identical regular tetrahedra together efficiently? This may help! From https://arxiv.org/pdf/1012.5138, brought to my attention by @liuyao

Have you ever read a C program that uses K&R function declaration syntax and C99 // comments in the same function? It seemed an unusual combination to me, but maybe it's not.

I've just come across this really nice animated explanation of the Demaine et al. theorem that hinged dissections always exist between two polygons that have the same area. https://youtu.be/kTka84UJp2I

I've just got this book. I hadn't realised that the whole thing is hand lettered!

Travelling from Heathrow Terminal 2 recently, I was struck by the unusual organic geometry of the Luis Vuitton cafe/shop there. It turns out it was designed by Marc Fornes, who has done a lot of interesting work of that sort. Here's his website: https://theverymany.com/ And a TED talk he gave […]

What Abbotsbury Road needs in that empty unit is a restaurant selling burgers, kebabs and pizza IN THAT ORDER.

There's a famous classification of fun into three types: https://essentialwilderness.com/type-1-2-and-3-fun/ If you draw this in a 2×2 matrix, it becomes clear there's one missing. I propose we refer to the missing type as Type 0 fun: enjoyable at the time but, in retrospect, regrettable.

I love the feeling of going to bed leaving a search algorithm running. Will it have found anything by the time I wake up tomorrow? So exciting.

I think this is the first time I've seen ChatGPT credited in the acknowledgements of a paper. https://arxiv.org/abs/2509.22333

New video: I went to see the Pascaline! They did not let me touch it. youtu.be/CROrLQpN6dc

I fear CAD could become a dangerous addiction.

This is up there with “Can One Hear the Shape of a Drum” in the annals of great titles. Was the 1960s an especially auspicious time for excellent titles?