Blog Posts
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When perimeter is equal to area
Some triangles have the same perimeter (in cm) as area (in cm²). For example, the 6-8-10 right-angled triangle: What properties of the triangle might signal that this sort of alignment of perimeter and area is possible? One answer I discovered to this question is completely surprising and delightful to me: If any of the side…
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It’s just subbing into formulas
(This blog post is a slightly expanded copy of a thread I wrote on Twitter in 2021.) I have met people before who say that statistics and applied maths are easy for students because it’s just subbing numbers into the right formulas. Sometimes it’s not quite so overt, and I just see people express frustration…
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Jenga Views
This blog post is about a sequence of visual perception and geometry puzzles I have created called Jenga Views. You can download a file here with 39 puzzles, roughly in order of difficulty. In my previous blog post, I showed two variations on traditional Jenga that I think are more interesting and more fun. But…
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Jenga Variations
In this blog post I will tell you about two variations to traditional Jenga that I find fun, and also reflect on what these say about what “fun” means to me. Original Jenga It’s best to discuss original Jenga before talking about the variations, just in case there are important things about Jenga you don’t…
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More wisdom from the Dodecahedron
After a long hiatus, I am dusting off my blog and I’ve moved it here to a new home. While I was going through the process of transferring everything here, I re-read the very first post I ever wrote, called Wisdom from the Dodecahedron. And I also found my drawing of the Dodecahedron that the…
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Making Maths Foundations
NOTE: I wrote this article in September 2025 for the University’s Learning & Teaching News, and I thought I would reproduce it here so other interested people could read it. Many people feel that their experience with maths up until now prevents them from approaching careers or courses that interest them. For example, a student…
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Complex lines with i-arrows again
Once upon a time (in 2016), I created a way to visualise where the complex points are in relation to the real plane, and then more recently (in 2022), I modified it to become the concept of i-arrows. I reread those blog posts recently while updating the blog to the new website, and I got all interested…
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Gerry-mean-dering
A recent video from Howie Hua showed how if you split a collection of numbers into equal-sized groups, then find the mean of each group, then find the mean of those means, it turns out this final answer is the same as the mean of the original collection. He was careful to say it usually…
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Making the lie true
We at my university regularly sell quite a big lie. At Open Day and the Ingenuity STEM Showcase and any number of outreach activities, students do puzzles and play with construction toys and walk around with ropes and draw curves on balloons. Whether we say it explicitly or not, there is a message there that…
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Introducing Digit Disguises with a small game
Because [reasons], my game Digit Disguises has been on my mind recently, and reading the original blog post from 2019, I suddenly realised I had never shared my ideas on how to introduce the game to a whole class at once. This blog post fixes that.