article muse.jhu.edu/pub/6/articl.... It didn't have too much about Byrne's calculus, but it did have this image of the frontispiece. So cool to see that again! Here are some images I made a few years ago of conic sections on circle/circle and circle/line graph paper.

At Bridges, @quiteclare.bsky.social spoke about Oliver Byrne and his version of Euclid's Elements. She mentioned that Byrne's last known work (unpublished but in the archives at Trinity College Dublin) was "The Trinal Calculus," which was his attempt to put calculus on a rigorous

Recently, I've seen a bunch of "Gen Z translation" videos explaining the slang of today's youth. Those videos remind me of the prank pulled on the NY Times in 1992, when they wrote about grunge, Seattle, and local slang. These terms were all made up by a record label employee.

At Bridges, I gave a talk about how to make "impossible objects" from curves defined in terms of functions of x, parametric, polar, and implicit equations. @standupmaths.bsky.social asked if a similar technique could be used for a curve given by an SVG file. Yes! Here are some proofs of concept.

I left my car in an outdoor parking lot near Washington Dulles Airport for 11 days while traveling. It must have been warm. A sealed seltzer can exploded, and the melatonin gummies melted into one massive gummy.

At family day at Bridges I volunteered to help Nick Sayers with his giant pantograph. Trace the outline of the person, and a small copy is drawn by the pen. It was fun for kids and adults of all ages. Here is @ayliean.bsky.social as a model and an artist. 

I saw this lovely design on the sidewalk in Galway. According to Google, it is a water main stopcock cover. The inscription "uisce" means "water" in Irish, and "WSC-R" stands for Water Service Control - Road.

A fun free coordinated motion puzzle from George Bell and Nan Ma.

Euclid illustrator Oliver Byrne married someone with last name Rugg. So her married name was the unfortunate Rugg Byrne.

More math tourism: the library at Trinity College Dublin. Now with busts of female scholars, like Ada Lovelace (2023).

Math tourism: Broome Bridge in Dublin, Ireland, where Hamilton discovered the quaternions!

The font was small, I was lazy, and I didn't want to count all the 1s. I copied and pasted into Google: "What is the number 1111111111?" Not the reply I expected.

I created this logic/grid deduction puzzle several months ago just to try out vibe coding. I created it for myself and have been enjoying playing it, so I thought I'd share it more widely. I call it Daedalus' Labyrinth. divisbyzero.github.io/Daedalus-Lab... Each segment in the grid must either

everything a 100% blend of its ingredients?" Today, I decided to ask Google's AI to explain it to me. It pointed me to this item of federal code: Title 21 / Chapter I / Subchapter B / Part 101 / Subpart B / § 101.30(b)(3) www.ecfr.gov/current/titl...

Who says AI is not useful? Here's today's use case. 🤣🤣🤣 This was my Facebook memory from 15 years ago. (I still think it is funny!) "We just bought this juice today. I don't understand what the '100%' refers to. 100% cranberry juice: no. 100% juice: no. All I can figure is 100% blend. But isn't

Here's my attempt at a duckling, plus the template for it.

Close-ups of the card suits

I made these card suits using curved origami techniques.

Happy Fourth of July! This is Old West on the campus of Dickinson College lit up for the 250th birthday celebration.

While watching the World Cup: Making a curved origami fish and cat.

Thanks! Here's the fold pattern I made. To get the usual 5-pointed stars with 36°/108° corners, you need to start with this 72°/144° unfolded star.

I folded this star shape. Is this a known origami pattern?

On a whim, I asked Claude to make one of those D&D alignment charts filled with historical math figures. Here's what it gave me. I then asked it to redo the activity, but to add some diversity—women, non-Europeans, etc. What do you think?

Serious question: Is "parabolic" now being used in this way in everyday language, like "exponential" is traditionally, to mean rapid growth? Being a New Yorker comic, I suspect it passed by competent editors and wasn't an error that slipped through.

The proceedings for the Bridges 2026 conference in Galway (August 4-8) are out! I'm very excited to go. My article in this volume is an update of an older article I wrote: "A New Method for Creating Impossible Cylinders" archive.bridgesmathart.org/2026/

We were in an Uber at about 11:00 last night at a stoplight and saw a drunk driver take a turn so sharp that they were 100% on the opposite sidewalk, hit this light post, and kept driving. No brake lights before, during, or after the collision. Terrifying. It was too dark and too far away for us

with a single strip of paper. But I made all the knots from two strips so I could get a larger object with a more pleasing fold angle.

Here are a few more curved origami pieces I made. Technically, I made them so the crease lies in the same plane. But if I make the strips narrow enough relative to the object's size, you can get the over-and-under behavior to work pretty well. I could have made all of these except the 5₁ knot

Two different figure-eight knots made with curved origami. The blue one has a fold angle of 90°, and the purple has a fold angle of 60°. The latter can be made with one strip of paper. The former required two.

Link to the book (which also has crease patterns that can be downloaded): mitani.cs.tsukuba.ac.jp/book/curved_...