S.ir Roger Penrose stands in front of the Mathematical Institute in Oxford wearing his tweed jacket, his hair fluttering in the wind, explaining the extraordinary rhomboid tile pattern he invented in the 1970s that covers the courtyard beneath our feet.
“This,” he says, using his walking stick, “is a pattern that appears to be orderly, but you can go on forever and it can never quite repeat itself. It’s beautiful. I rather like to walk on it. “