I made this. Here’s how…

# You're reading: Travels in a Mathematical World

### Christmas images using parabolic curves and TikZ

Katie is running an Aperiodical advent calendar (Aperiodvent 2018), with fun maths Christmas treats every day. Behind the door for 7th December was Parabolic Sewing.

This is not unrelated to what I submitted as my entry to The Big Internet Math-Off last summer. I have been revisiting this idea ready for a class next week in my second year programming module.

### LaTeX/TikZ to draw a star graph $K_{1,n}$

For a diagram for a class this week, I’ve written a LaTeX command to draw star graphs using TikZ. A star graph $K_{1,n}$ is a graph with a single central node, $n$ radial nodes, and $n$ edges connecting the central node to each radial node. I am sharing this here in case it is useful to anyone else.

### Baking Babylonian cuneiform tablets in gingerbread

The MathsJam conference has a baking competition. My friend the archaeologist Stephen O’Brien tweeted a while ago a link to a fun blog post ‘Edible Archaeology: Gingerbread Cuneiform Tablets‘. Babylonian tablets are among the earliest written evidence of mathematics that we have, and were produced by pressing a stylus into wet clay.

So it was that I realised I could enter some Babylonian-style tablets made from gingerbread.

I made a gingerbread reconstruction of a particular tablet, YBC 7289, which Bill Casselman calls “one of the very oldest mathematical diagrams extant“. Bill writes about the notation on the tablet and explains how it shows an approximation for the square root of two. I’m sure I didn’t copy the notation well, because I am just copying marks rather than understanding what I’m writing. I also tried to copy the lines and damage to the tablet. Anyway, here is my effort:

In addition, I used the rest of the dough to make some cuneiform biscuits. I tried to copy characters from Plimpton 322, a Babylonian tablet thought to contain a list of Pythagorean triples. Again, Bill Casselman has some interesting information on Plimpton 322.

Below, I try to give a description of my method.

### Handing over @mathshistory

On 5th October 2010, eight years ago this week, I sent a tweet from a Twitter account I had registered on behalf of the British Society for the History of Mathematics (BSHM). I was on BSHM Council at the time and, mindful of the Society’s charitable aim to develop awareness of the history of mathematics for the public benefit, I proposed starting a Twitter account. I thought a good way to generate a background level of activity for the account was to tweet a daily mathematician, taking my lead from the MacTutor website facility. So I set up @mathshistory and sent the first tweet, announcing the anniversary of the birth of Bernard Bolzano.

Bernard Bolzano (1781 – 1848) worked to "free calculus from the concept of the infinitesimal" and was born on 5 Oct http://bit.ly/9TV331

— Maths History (@mathshistory) October 5, 2010

### LaTeX for typesetting a multi-pile Nim game

I am preparing to teach our new final year module ‘Game Theory and Recreational Mathematics’. So I’m thinking about game typesetting in LaTeX (texlive-games is useful in this regard). I was looking for an easy way to display multi-pile Nim games. Usually, I find searching “latex thing” finds numerous options for typesetting “thing” in LaTeX, but here I was struggling.

Nim objects could be anything, of course, but conventionally sticks or stones are used. There are various types of dot in LaTeX that might look like stones, but somehow a line of dots didn’t seem satisfactory. There are various ways to draw a line (not least simply typing ‘|’), including some tally markers (e.g. in hhcount). My problem with these (call me picky) is that they are all identical lines, and a ‘heap’ of them just looks very organised. Really, I want a set of lines that looks like someone just threw them into heaps (though probably without crossings for the avoidance of ambiguity). So I wrote my own.

### Second place in a single-elimination tournament

I made a silly joke, and it made me think.

You may be aware that our own Christian Lawson-Perfect is running the Big Internet Math-Off here at the Aperiodical, a single-elimination tournament with sixteen competitors. I was knocked out in round one by the brilliant Alison Kiddle. I joked that if Alison went on to win, then I’d be joint second.

Much as I like and respect @ch_nira, I’ll be rooting for @ajk_44. If she goes on to win the #BigMathOff final and is crowned The World’s Most Interesting Mathematician, then I’m joint-second, right? https://t.co/8Jt37gHFif

— Peter Rowlett (@peterrowlett) July 10, 2018

I’ve been mulling this over and I felt there was something there in thinking about the placement of the non-winners in such a tournament, so I had a play.