> It would be one of those formally correct but practically useless definitions.

"Hi, my name is Aperiodic, and I'm... a mathematician."

"Hi Aperiodic."

"It all started out so easily; you know, a few lemmas with the boys in the evenings. But before I knew it, I was picking up Bourbaki as soon as I got home from work. I would wake up in the mornings, surrounded loose sheets of paper covered in commutative diagrams, without a clear idea of what I did last night..."