Maths etc. 🌉 bridged from ⁂ https://mathstodon.xyz/@robinhouston, follow @ap.brid.gy to interacthttps://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gyhttps://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mlbs4zru4xy2Have you ever wanted to see a twisty puzzle that represents the Mathieu group M₂₄? Man is this your lucky day! https://youtu.be/xwQ5dx4dE9g07 May 2026 17:58 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mlbs4zru4xy2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mlbpy3yzxr22RE: https://mathstodon.xyz/@pieter/116534285031160547 This is really fun! I wonder if it will become more common for papers to be accompanied by apps, as the barrier to app creation is lowered. https://mathstodon.xyz/users/pieter/statuses/11653428503116054707 May 2026 17:19 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mlbpy3yzxr22https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3ml6kdgyvndj2RE: https://mathstodon.xyz/@tao/116477353989159599 This is a nice analogy. https://mathstodon.xyz/users/tao/statuses/11647735398915959906 May 2026 11:00 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3ml6kdgyvndj2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mksahicclwo2I want to know the relative popularity of the Platonic solids, but a Mathstodon poll can have at most four options.01 May 2026 13:31 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mksahicclwo2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mka2gpjczf42RE: https://mathstodon.xyz/@de_Jong_Tom/116458595973450171 It's interesting and exciting to see this place start to be recognised in slightly more formal venues. (It slightly reminds me of when the internet as a whole was rather disreputable, which honestly I preferred.) https://mathstodon.xyz/users/de_Jong_Tom/statuses/11645859597345017124 Apr 2026 07:56 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mka2gpjczf42https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mk7uoogmj642I thought Peter Selinger was on here, but I can't find him. Has he left us? Just looking at this interesting new paper https://arxiv.org/abs/2604.20964 which does cite Mathstodon posts by @pieter. (@christianp first citation of Mathstodon in a paper, or have there been others?)24 Apr 2026 06:13 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mk7uoogmj642https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mk5taai2jwq2RE: https://mathstodon.xyz/@henryseg/116437443825536011 This is now my favourite physical object. https://mathstodon.xyz/users/henryseg/statuses/11643744382553601123 Apr 2026 10:41 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mk5taai2jwq2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mk46xvgkcne2Meet the zonohedrification of the rhombicosidodecahedron. https://skfb.ly/pIOIO https://sketchfab.com/3d-models/zonohedrified-rhombicosidodecahedron-0bc66439ab3b41779edcd2233974f7be22 Apr 2026 19:06 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mk46xvgkcne2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mk3ufygaxtn2Spotted in The American Mathematical Monthly, Vol. 99, No. 2 (Feb., 1992)22 Apr 2026 15:57 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mk3ufygaxtn2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mk2xv2otfpl2This is rather amazing: a set of 3d-printable adapters making it possible to connect pieces from nine different construction kit toys. https://fffff.at/free-universal-construction-kit/22 Apr 2026 07:27 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mk2xv2otfpl2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mjymqbrs5es2I knew about the https://en.wikipedia.org/wiki/Teapotahedron, of course, but the https://en.wikipedia.org/wiki/Zocchihedron is new to me.21 Apr 2026 09:02 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mjymqbrs5es2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mjmtrp5xaia2I didn’t realise this article was out already! Featuring some computations and diagrams by me (which, to my great excitement, Don Knuth emailed me about when he heard of them). _On Max Bill’s gelbes feld_ by Barry Cipra. https://www.ams.org/journals/notices/202605/noti3334/noti3334.html I […] https://mathstodon.xyz/@robinhouston/11641535632510242916 Apr 2026 16:36 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mjmtrp5xaia2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mjktqg6zxcd2There’s a fun paper showing that you can define all elementary functions using just two primitive operations: the constant 1, and the binary function eml(x, y) := e^x - log(y). https://arxiv.org/abs/2603.21852 That’s a neat little result, which makes for some fun games. What’s the simplest […] https://mathstodon.xyz/@robinhouston/11641085140829733415 Apr 2026 21:30 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mjktqg6zxcd2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mjkicxb3quw2I guess we’re all getting a little tired of talking about this sort of thing, but I think this is the most impressive example yet of an LLM-generated solution to a long-open mathematical problem: https://www.erdosproblems.com/forum/thread/1196 Jared Lichtman, a mathematician who has spent (in […] https://mathstodon.xyz/@robinhouston/11641004775725705215 Apr 2026 18:06 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mjkicxb3quw2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mjk3u2uw42a2RE: https://mathstodon.xyz/@krystalguo/116408728086548168 It's rather charming that this sort of encouragement makes AlphaEvolve work better.15 Apr 2026 14:22 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mjk3u2uw42a2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mjie7anewhn2Unfortunately there is no way I can persuade you to watch this by quoting a particularly amusing moment, because there are so many particularly amusing moments that I can’t possibly choose one. https://youtu.be/M1si1y5lvkk Here’s the paper, in case you’re more of a reader than a viewer […] https://mathstodon.xyz/@robinhouston/11640525449292232514 Apr 2026 21:47 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mjie7anewhn2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mjiareywkun22025 was the first squared-triangled-squared-triangle number for 2024 years, and I spent the whole year not knowing that! https://youtu.be/aulrY8Y4VW814 Apr 2026 20:45 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mjiareywkun2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mjbwgdrkchu2Is math big or small? https://chessapig.github.io/talks/Big-Small12 Apr 2026 08:24 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mjbwgdrkchu2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mj5a26cm5di2I don't remember coming across the Heptagon Numbers before. Very nice!10 Apr 2026 11:32 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mj5a26cm5di2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mixy34mcfjs2Did you know that there's a spherical analogue of Heron's formula? (TIL) https://mathworld.wolfram.com/LHuiliersTheorem.html08 Apr 2026 09:27 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mixy34mcfjs2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mi2dmyx5r562Speaking of Hoffman’s packing puzzle (as I recently was), I just found out about Oskar van Deventer’s witty mashup of Hoffman’s packing puzzle with Piet Hein’s Soma Cube: https://www.puzzlemaster.ca/browse/3dprinted/16775-hoffman-soma27 Mar 2026 14:34 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mi2dmyx5r562https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mhqtlknvbki2This is mildly interesting: It looks as though current LLMs are becoming at least competitive with expert humans at solving Diophantine equations. Here a new MO contributor has used GPT 5.4 to find solutions to a couple of Diophantine equations that were posted by Bogdan Grechuk in 2023, and […] https://mathstodon.xyz/@robinhouston/11628023637053438923 Mar 2026 19:53 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mhqtlknvbki2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mhnxwr33tho2Clever.22 Mar 2026 16:32 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mhnxwr33tho2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mhly6wcrbck2Does this really work? I wish I had known when I were younger.21 Mar 2026 21:32 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mhly6wcrbck2https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mhbgq77d4a32“The puzzle in the photograph is now in the collection of HRH Prince Charles.” https://puzzleworld.org/PuzzleWorld/puz/holey_squares_cube.htm Apparently the King collects geometric puzzles!17 Mar 2026 16:53 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mhbgq77d4a32https://bsky.app/profile/robinhouston.mathstodon.xyz.ap.brid.gy/post/3mh7acfn3b4s2I just stumbled across this. I haven’t tried it yet. (It’s printing now.) I had not heard about this interesting discovery! https://www.printables.com/model/221119-knuths-packing-puzzle “In 1978 Hoffman proposed that a if you take cuboids with size A×B×C, you can always pack 27 into a cube […] https://mathstodon.xyz/@robinhouston/11624059867637780516 Mar 2026 19:52 +0000at://did:plc:nhakixcsmdow4avnqxtfy6c6/app.bsky.feed.post/3mh7acfn3b4s2