# BLOGS WEBSITE

# Category: Isn’t maths cool?

Anything about maths concepts or processes that I think is really cool.

#### Quarter the Cross: Connect the Dots

This blog post is about a new variation on the classic Quarter the Cross problem, which I call Quarter the Cross: Connect the Dots.

Background

Here is the original Quarter the Cross problem:

To catch you up, here is everything I’ve written about Quarter the Cross up until now:

Quarter the Cross — in which I first learn about […]

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#### Number Neighbourhoods

This blog post is about a game I invented in February 2020, the third in a suite of Battleships-style games. (The previous two are Which Number Where and Digit Disguises.)

NUMBER NEIGHBOURHOODS: A game of analytic deduction

Players:

This game is for two players, or two teams.

Setting up:

Each player/team choose six different numbers between 0 and 10 (not including 0 […]

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#### Where the complex points are: on a real circle

Introduction

In 2016 I created the iplane idea, which allows you to locate the complex points on a real graph.

In case you haven’t heard of it or you need reminding, the idea is that at every real point (p,q) of the real plane, there is a planes-worth of complex points attached, all of which have coordinates […]

#### Quarter the Cross: Colouring

Quarter the Cross is one of my favourite activities of all time, whether in maths or just life. I learned about it way back in 2015 and have been mildly or very obsessed with it ever since. You can read about my obsession in my first Quarter the Cross blog post, and you can read […]

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#### Return to the iplane: A complex line

It’s been four years since I came up with the idea of iplanes as a way to organise the complex points on a graph, and in the intervening time I have thought about them on and off. For some reason right now I am thinking about them a lot, and I thought I would write […]

#### Digit Disguises

This blog post is about a game I invented this week, and the game is AWESOME, if I do say myself.

DIGIT DISGUISES: A game of algebraic deduction

Players:

This game is designed for two players, or two teams.

Setting up:

Each player/team has two grids with the letters A to J, one labelled MINE and one labelled THEIRS, like the […]

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#### Zooming in to see the slope

A lot of people introduce the derivative at a point as the slope of the tangent at that point, which to me is quite confusing. It seems to me that the reason we want the derivative is that it is a measure of the slope of our actual function at that point, not the slope […]

#### Ten years

On the 23rd of July 2008, I started my first day as coordinator of the Maths Learning Centre at the University of Adelaide. Today is the 23rd of July 2018 — the ten year anniversary of that first day. (Well, it was the 23rd of July when I started writing this post!)

So much has happened in […]

#### The Human Galton Board

Last week we were booked in to do Human Markov Chains with several groups of school students, but it turned out there would be a lot fewer of them than we expected, and I didn’t think Human Markov Chains would work very well with under 20 students. I still dearly wanted to do a moving […]

#### Human Markov Chains

This blog post is about a moving maths activity that I have wanted to do for years and finally got an opportunity to do this year in 2018. It’s a model of a concept called a “Markov Chain” using human movement.

In a Markov chain, there is a thing that can be in any number of […]