The Christchurch Maths Craft Day Free Public Talks

11am Four Colours are Enough Jeanette McLeod, University of Canterbury

1pm Zigzags, , and Pleating Michael Langton, University of Canterbury

3pm Chaos in and Steel Bernd Krauskopf & Hinke Osinga,

The Recital Room Chemistry Building 23 May 2021

Maths meets craft in this series of public talks, accessible to everyone!

Public Talk Summaries

All talks will be held in the Recital Room in the Chemistry Building.

Four Colours are Enough (Dr Jeanette McLeod) How many colours are needed to colour a map so that no two regions sharing a border are coloured with the same colour? What if you had to use the fewest number of colours possible? Mathematicians took over 100 years to find the answer to this question, and the result is one of the most controversial theorems of the 20th century! In this talk we will discuss the history of the infamous Four Colour Theorem, explain why mathematicians have struggled with it so much, and explore its links with crafts such as knitting, quilting, and colouring.

Zigzags, Fractals, and Pleating (Dr Michael Langton) Pleating fabric is a mathematically fascinating and historically fashionable craft involving folded patterns that often look like zigzags. Everyone understands zigzags, but how do you make folding zigzags efficient? What happens if the zigs and zags don't alternate perfectly? What happens if you do infinitely many of them? How do you fold a two-dimensional zigzag? What even is a two-dimensional zigzag? How many different fold patterns are possible? Exploring the answers to these questions will take us through papercraft, fractals, and the mechanics of pleating fabric yourself.

Chaos in Crochet and Steel (Prof Bernd Krauskopf & Prof Hinke Osinga) Bernd Krauskopf and Hinke Osinga are both Professors in Applied at the University of Auckland, and they study how chaotic behaviour arises and can be explained mathematically. Their research led them into unexpected directions of craft and art when they realised that they could turn their computer-generated images of the famous chaotic Lorenz weather model into a concrete model via crochet. The so-called Lorenz manifold embodies the underlying unpredictability in an intriguing and hands-on way. At over 25,000 stitches, the crocheted piece is about a metre wide and has been the subject of considerable media attention worldwide. The amazing mathematical properties of the Lorenz manifold also caught the attention of artist Benjamin Storch, who turned it into a steel sculpture. Hinke and Bernd will highlight some of the underlying geometry and their journey from maths into craft and art.