We all know mathematicians are the coolest people on the planet. But it turns out that of all the people not on the planet, all of them are in fact either mathematicians, or have mathematical backgrounds or training. Astronauts – and Russian cosmonauts – are all super mathsy people, and if they weren’t already awesome enough, this really seals the deal for me.

# Right answer for the wrong reason: cellular automaton on the new Cambridge North station

Cambridge North is a brand new train station, and the building’s got a fab bit of cladding with a design ‘derived from John Horton Conway’s “Game of Life” theories which he established while at Gonville and Caius College, Cambridge in 1970.’

One problem: that’s Wolfram’s Rule 135, not the Game of Life. You can tell because of the pixels.

Rule 135 is a 1-dimensional automaton: you start with a row of black or white pixels, and the rule tells you how the colour of each pixel changes based on the colours of the neighbouring pixels. The Cambridge North design shows the evolution of a rule 135 pattern as a distinct row of pixels for each time step. Conway’s Game of Life follows the same idea but in two dimensions – a pixel’s colour changes depending on the nearby pixels in every compass direction.

Either way, it’s a lovely pattern. I suspect the designers went with Rule 135 instead of the Game of Life so that they’d get a roughly even mix of white and black pixels, which is hard to achieve under Conway’s rules.

Just in case gawping at train stations is your cup of tea, here’s a promotional video with lots of lovely panning shots of the design:

### More information

Delayed £50m Cambridge North railway station opens on BBC News.

Cambridge North Station information from Atkins Group, the design consultancy responsible for the station building.

Press release from Greater Anglia trains.

The Game of Life: a beginner’s guide by Alex Bellos in the Guardian.

*Brought to our attention by @Quendus on Twitter.*

# We want your best #proofinatoot on mathstodon.xyz

Mastodon is a new social network, heavily inspired by Twitter but with a few differences: tweets are called toots, it’s populated by tusksome mammals instead of little birds, and it’s designed to run in a decentralised manner – anyone can set up their own ‘instance’ and connect to everyone else using the GNU Social protocol.

Colin Wright and I both jumped on the bandwagon fairly early on, and realised it might be just the thing for mathematicians who want to be social: the 500 character limit leaves plenty of room for good thinkin’, and the open-source software means you can finally achieve the ultimate dream of maths on the web: LaTeX rendering!

# Alexandre Grothendieck’s notes archive to be released online

News from France, where the family of the late Alexandre Grothendieck, legend of basically all maths, have finally reached an agreement with the academic community about his huge archive of written notes. Discussions have been ongoing for a while but it’s finally been agreed that the notes can be released online for the community at large to take advantage of.

The notes comprise over 100,000 pages of mathematics, diagrams and letters to collaborators, and an initial chunk of over 18,000 pages will be online from 10th May on the University of Montpellier’s website. It’s expected that many undiscovered mathematical treasures might be found within, although the challenge of reading through and deciphering it all may take a Polymath-style mass effort.

### More information

The notes of the mathematician Alexandre Grothendieck arrive on the net, at Libération (in French)

# Carnival of Mathematics 145

Welcome to the **145th Carnival of Mathematics**, hosted here at The Aperiodical.

If you’re not familiar with the Carnival of Mathematics, it’s a monthly blog post, hosted on some kind volunteer’s maths blog, rounding up their favourite mathematical blog posts (and submissions they’ve received through our form) from the past month, ish. If you think you’d like to host one on your blog, simply drop an email to katie@aperiodical.com and we can find an upcoming month you can do. On to the Carnival!

# Review: The Mathematics of Secrets by Joshua Holden

Any book on cryptography written for a more-or-less lay audience must inevitably face comparisons to *The Code Book*, written in 1999 by Simon Singh, the king of distilling complex subjects to a few hundred pages of understandable writing. While Singh’s book is a pretty thorough history of codes and codebreaking through the centuries with plenty of the maths thrown in, *The Mathematics of Secrets* is tilted (and indeed titled) more towards a fuller explanation of the mathematical techniques underlying the various ciphers. Although Holden’s book follows a basically chronological path, you won’t find too much interest in pre-computer ciphers here: Enigma is cracked on page seventy, and the name Alan Turing does not appear in the book.

# Video: How to draw an egg

Katie’s done another video! This time it’s a neat method for constructing an egg-shape, using arcs of circles.

Bonus challenge: See if you can count how many times Katie accidentally says ‘compass’ instead of ‘pair of compasses’ during the video.