When I worked in London one of my skills was to make patterns. At the time I was working for a company that produced very expensive one-off coats and each pattern was made to fit an individual customer. Our clients were mostly the rich and famous who didn’t have time to do more than one fitting so my patterns had to be accurate. When I began it wasn’t my area of expertise but I enjoyed the challenge and having made clothes since I was six it didn’t seem difficult although my boss called my method ‘applied guesswork’.
Most people are familiar with commercial dress-making patterns, flimsy tissue-paper sheets which are highly inaccurate and produce mixed results. I’ve had terrible failures with such patterns and when you’ve spent a fortune on beautiful fabric it’s really sad to find the result of your labours isn’t wearable. So I can sympathise with Sir Christopher Zeeman, emeritus professor of applied mathematics. When he couldn’t find a dressmaker to make a dress for his wife with the piece of hand-woven silk he’d brought from Thailand (it wasn’t long enough) he decided he would make it himself.
First he measured his wife carefully and worked out her ‘area’ in square inches. He’d never made a dress before and thought a sleeveless summer dress with a simple princess line would be the most simple to design and make. Luckily he produced a mock-up using an old sheet, because it all went horribly wrong.
‘I was particularly intrigued by the negative curvature at the small of the back.’ He said when discussing the problems during a lecture at Gresham College. ‘I slowly began to realise that I did not yet understand the basic mathematical problem of how to fit a flexible flat surface round a curved surface.’
Being ‘mathematical’ he decided he would analyse the best means to produce the necessary ‘fitted’ effect and discovered what a dressmaker calls a ‘dart’. Then, after a long and well-reasoned study of darts, he decided to write a mathematical equation that could provide the correct ratio required for a perfect fit – ‘the first approximation is to assume that the cross-section at the hips is a circle of radius r, and that at the waist is a smaller circle of radius r-x. Hence the hip to waist ratio is 2π(r-x).’
But then he encountered the ‘different vertical asymmetry’ between his wife’s back and her front. No more negative curvature, in fact there was the added problem of a bust. Subsequently he had many sleepless nights considering the best way to finish the dress because ‘there was a deep topological obstruction, analogous to the impossibility of unknotting a knot.’
Lady Zeeman commented that her husband so enjoyed his delve into the mathematics of dressmaking he worked on several projects, still in frequent use.
My point being that many English schools dropped the teaching of dressmaking when the National Curriculum decided in favour of more ‘technical studies’ such as computer skills but perhaps they would have been better taking Sir Christopher’s approach to problem solving?