There are some things that we use every day without realising that someone created them. Take mathematical symbols. “+” was first introduced by Nicole Oresme in 1360, “×” by William Oughtred in 1618, and “÷” by Johann Rann in 1659. The god of them all, “∞”, came in 1655. Humans had spent centuries trying to understand infinity, and in his “Treatise on the Conic Sections”, the English mathematician John Wallis introduced a symbol that expresses it. For me, it is the most intelligent piece of graphic design in the world. To say something in a complicated way is very easy. But to find a way to say it simply – that takes a lot of work.

As a designer I wake up every day hoping to have a good idea, to be useful. But I also want to be able to communicate and share that idea, that vision. To do that I need to find the clearest visual language I can. If I stick to a language that 12 people can understand, it suggests that I don’t care if anyone comprehends or not. It’s elitist. Wallis’s genius was to choose a symbol which, with its endless shape, is so clearly related to the concept that everybody agreed to use it. Mathematical signs form our only universal language. That’s why, if I’m asked if there’s anything I wish I had designed, it is this.

Philippe Starck is a French inventor, designer and architect. He has had solo shows at the Guggenheim in New York and the Pompidou Centre in Paris. He was talking to Simon Willis

I have a special relationship with these signs, but not because I am good at maths. I was totally ill-adapted to school. I was designing all the time from the age of six or seven, when during the holidays, a pure crystal of boring time, I began making my own toy cars. They were beautiful and they worked. But at school I felt like I was in jail, and I learned nothing. I spent my time drawing at the back of the class. I even designed, when I was ten or 12 years old, a room in which to torture my schoolmaster. It was very advanced for my age, and very well planned. In the end we came to a deal. If I agreed to be quiet, the school would allow me to draw.

But later I came to understand the value of mathematics for me, and my intimate relationship with it. I am a little autistic, and like many autistic people, I sometimes find it easier to communicate with colours or symbols than with words. To me, the signs of mathematics are a set of visual metaphors for ways of feeling. “±” is a sign meaning that there are two different possibilities which are equally valid – a symbol of uncertainty. “∞” is about the fight we have with ourselves to try to understand more and more. And when I’m designing something, I say that I first have to get to the “√”, the square root of the problem: the feeling that I have got to the core of it, from which I can build out. The goal is always to convey an idea in the purest way I can.

That is why I admire Wallis’s symbol. When he introduced the sign for infinity, he achieved the goal that all good design should aim for: elegance.

ILLUSTRATION KATHRYN RATHKE