As he sat on the train to Cambridge, it dawned on him that since none of his classmates would be joining him at university, he would be able to transform himself into a new person: an extrovert! He wasn’t sure it would work. He worried that his introversion might be too entrenched, but he decided to try. He would be boisterous and witty, he would tell funny stories at parties, he would laugh at himself – that was key.

“Roughly speaking,” he recalled, “I was going to become the kind of person you see now. It was a free decision.”

Siobhan Roberts, John Horton Conway: the world's most charismatic mathematician, The Guardian, 2015