The Aperiodvent Calendar, 2015

Everyone enjoys counting down to Christmas so much, that it seems to happen earlier and earlier each year. Well, sticking to the standard format of counting from 1st December down to 25th using a specially prepared calendar, we present the Aperiodical’s 2015 Advent Calendar, featuring behind each door not a small disappointing piece of chocolate, but a randomly chosen nugget of mathematical goodness for your enjoyment.

From YouTube videos to websites cataloguing number sequences, we’ve got a nice surprise for you each day. We’ll be adding each door as a post on the site, plus you can find them all collected together below, along with interesting number facts. Enjoy!

What I’ve done this year


I gave a talk at the big MathsJam conference at the start of this month. It happens annually, so I had a whole year to come up with something interestingly mathematical to entertain my fellow mathmos.

When it came time to decide on a topic, I realised I’ve done loads of stuff this year! It was really hard to choose. So, now MathsJam is over, I thought I’d collect together all the mathematical things I’ve done in the last 12 (-ish) months.

plotly.js is now open source

plotly is a fairly comprehensive tool for creating whizzy interactive charts from data. It provides a suite of tools to make a whole range of different types of charts.

Until now, it’s been a web service you send data away to in order to get a chart back. I’d always been wary of that, because I worry about what happens when Plotly the company gets sold off or goes bust, and the service gets shut down.

Well, now I can use a little bit of, because they’ve released the bit of the chart-drawing code that runs in your browser under the MIT open source licence, meaning anyone can use it independently of Plotly’s servers.

With just the open-source stuff, the process of creating a chart is quite torturous because you have to define what you want by following a fairly illegible JSON schema. That means there’s still a reason to use the proprietary stuff that gives you a nice interface from Python or R, though I suppose people will soon enough start making their own versions of those that just tie into the Javascript stuff.

More information

Plotly.js Open-Source Announcement

plotly.js on GitHub

Ask Clever Hans a question

I’ve put a very clever horse on the internet. He’s called Hans and I’ve made a little video about him.

You can ask Clever Hans your own questions! Go to and make sure your microphone is turned on. Another proviso: I think only Google Chrome supports the special technology I used to make Hans work. Sorry!

I’ll explain how Hans does his horsey magic below the fold.