Cool! The circles in an Apollonian Gasket can all have an equation of the form (n|x|-a)² + (n|y|-b)² = 1, where n is a positive integer, and a & b are non-negative integers < n. www.desmos.com/calculator/6... #MathSky #iTeachMath

As pointed out by @paulakrieg.bsky.social and noted by @mpershan.bsky.social, longtime #mtbos partner and collaborator Malke Rosenfeld passed away last year. She investigated and taught the mind-body math connection, engaging hundreds of teachers and learners in #mathart - dance! RIP great friend!

This quiet week is for art. Sharing daily something marvelous I've seen. First up: Oliafur Eliason at the Hirschhorn. One light source, one rotating crystal ring, a white wall. That is all.

Look what I made!

It's done! And ahead of schedule... (for once!) A fully revised 2026 version of the Risps PDF eBook is now available for free, from www.risps.co.uk and from Payhip. payhip.com/b/RGKPF An early Ch-risp-mas present? With best wishes of the season, Jonny

Meditate on the sweep of a spacefilling curve as a mandala.

Made a site comparing the sizes of living things :) The great Julius Csotonyi spent 5 months painting over 60 illustrations for the site, no ai used > neal.fun/size-of-life/

My new book is now available for preorder and I’m pretty psyched. Writing this book has been a passion project and a joy (and how lucky am I to be able to say that). It’s not due out until late spring/summer but seeing it online is really exciting for me.

I never public speak. But I’m going to be speaking at a conference I’ve gone to many times and have enjoyed for high school math teachers, in North Carolina. It’s late February. tcm.ncssm.edu I’d love to see fun math teachers there! #mtbos

Wow the word bocconcini has a lot of letters. It would be great fuel for one of those combinatorics problems.

I'm hooked on Hitomezashi too. I've even used it to mend something (coded in Turtlestitch and machine embroidered) and I've also experimented with patterns from recurring decimals. Have fun!

The Journal of Mathematics and the Arts invites applications for Editor-in-Chief from scholars who understand that mathematics and art are not separate worlds. Help us showcase research that reveals the mathematical soul of creativity. spr.ly/63321AhlWd

@mathskath.bsky.social Guess what came in the mail today?!? I flipped through it and I’m already in love! 🥰

I learned this folding technique yesterday, so I had to make something with it.

εεεεδεεεεδεεεεδεεεεδ... Every four ε, there is a δ.

non-Euclidean geometry proofs where the two columns eventually meet 💡

lotta math classes teach about completing the square without ever asking why the square felt incomplete in the first place 😔

Lorenz attractor. The most famous chaotic attractor in history, discovered by Edward Lorenz in 1963. Made with #python #numpy #pygfx

Sunday night seems the right time to post a gallery of (I hope!) every one of Catriona's geometry puzzles. notes.mathforge.org/notes/publis... Give it a moment to load ... there's a *lot* of them! #GeometryPuzzles #UKMathsChat #mathsky

We're disappointed to see Ben Barres's powerful book "The Autobiography of a Transgender Scientist" among the ~400 titles removed from the Naval Academy Library. Needless to say, we're proud to have published his book and will keep it — and his memory — alive.

Giant cardioid: version 2.5. Version 1.0 was made using Pex tubing and grommet tape. Version 2.0 was made from laser-cut pieces. The wood was too fragile, and it broke during construction. In version 2.5, I made the pieces wider and I used thicker wood. Success, I'd say! The diameter is about 5 ft.

Understanding geometry through model making

Hi Blue Sky! I edit the Journal of Humanistic Mathematics. We publish articles, essays, #fiction & #poetry on doing, teaching & living of #mathematics. So far we had more than 850K full-text downloads of our content - why not check us out? scholarship.claremont.edu/jhm/ #math #openaccess #mathart

A polynomial #visualpattern

The new surface-colouring option in @desmos.com 3D allows a cute way of visualizing conic sections. www.desmos.com/3d/fiv5gnltdl (The option to have translucent surfaces doesn't save with the graph itself, so needs to be re-toggled on. It's important for seeing the full curves) #MathSky #iTeachMath

I met with my knot theory independent study students today. The topic: braids. I broke out these "BraidTiles" that I made several years ago. You can download a printable pdf here (recommendation: print them on cardstock): divisbyzero.com/2019/05/01/b...

Images from my math teaching life yesterday and today. #mtbos

😃 Now you can define colors in the @desmos 3D calculator that depend directly on coordinates. www.desmos.com/3d/s40shr66rn

🌈 😃 Now you can now define colors in the @Desmos 3D calculator that depend directly on coordinates. www.desmos.com/3d/42d0f0d88f

Free Online Math Materials A blog post on linear algebra, taken from the students' preface to my free (gratis) book, with links to interactive software for matrix multiplication and exploring the geometry of linear transformations. www.diffgeom.com/blogs/about-... #MathSky #ITeachMath

About to do triangle congruency methods, which is the exact topic that Jesse Spano overdosed on caffeine pills to study

new @cshor.org pset 🏃💨 drive.google.com/file/d/1NaXQ... screenshots of PDF pages 1, 2, 3, and 10 below cc #iTeachMath ♾️ bcc #MathSky 🧮

It is *still* unknown whether or not every triangle admits a periodic billiard trajectory. Every triangle with rational angles does. And so does every obtuse triangle of at most 112.4 deg. "112.5 appears to be a natural barrier." gwtokarsky.github.io. #MathSky #Mathematics #Geometry #Billiards

Announcing the next MAA President and Vice President! Edray Goins will serve as MAA President-Elect and Yvonne Lai as Vice President starting July 1, 2026. Learn more about their vision and leadership: https://maa.org/news/announcing-the-next-maa-president-and-vice-president/

Today I realised that “integrates like” is the phrase I’ve been missing for talking about spotting the structure of an integral. #ALevelMaths #MathsToday

Timeline palate-cleanser: some pretty geometry in @desmos.com www.desmos.com/geometry/wgp... #iTeachMath #MathSky

I recently worked on a fun problem involved the Pokémon TCG. Here's a post about the problem and my thought process/solution. jclevelandtran.com/2025/10/15/s...

a million years later, this is still the neatest thing I've ever made, with huge help to the person at TMC13 (!) who figured out how to make the planets orbit www.desmos.com/calculator/d...

[digging through my twittxr archives] do you want non-routine quadratic problems? here are 20 💌: www.desmos.com/calculator/d... cc. #iTeachMath #MathSky #EduSky #AlgebraSky

Loved this HS student's #fractal, so #geogebra'd it up mathhombre.tumblr.com/post/7970450... #mathart

#Mathstoday Year 10 found expressions for shaded areas. Made this last year for an extension but it was nice spending a bit longer on it.

This is always a fun day in precalc - lots of friendly arguments

Finally! A citable writeup for @jennalaib.bsky.social! And, as linked in the article, there is the trove of examples freely available at: slowrevealgraphs.com #iTeachMath ♾️

Here is a @desmos.com activity about the symmetry-preserving transformations of a square, inspired by my colleague Tom Jameson. classroom.amplify.com/activity/68c... For a really great intro to how this relates to group theory, see this by @stevenstrogatz.com archive.nytimes.com/opinionator....

I saw this at the Brooklyn Botanic Gardens. I call it Powers of Two :) #mtbos

Never saw a graphical description of the difference of squares factorization so I made one. I don't know why.

On Friday at Noon (EDT) I am giving a talk in the New York Combinatorics Seminar. The title is: "Mathematical illustration through a combinatorial lens" in which I share my decade-long journey as a mathematical artist and jewelry maker and how it intertwines with my combinatorics research.

Finished a cape thingie that I started knitting in August. I learned a few more basic knitting skills (mainly making short rows/turning) but it’s still very beginner even though it looks fancy! It’s a free pattern on ravelry: www.ravelry.com/patterns/lib...

The 8 SMP's are new in MN so we are creating lots of resources. If you want a refresh, check out our stuff. Today we released a free resource anyone can use (K-2 3-5 6-8 HS & educators) to notice the assets of others engaging in the SMPs. Learn more here: www.youtube.com/watch?v=2NS_...

Patrick's @mrhonner.com.web.brid.gy is mostly on mathstodon, but he's thinking about #buildingthinkingclassrooms mrhonner.com/archives/21746