Mathematicians have the reputation for being a bit odd, don't they? My brother was one, a prof at a uni in Canada. He got ill some years ago, brain damage, no more working for him. Shame he was only 53 at the time, now family is looking after him. He still got more money than the rest of us though, think he gets pension, we had his nice house in Montreal sold after the onset of his illness.
Anyway, we used to talk some math. I did some uni courses in it. I recall when I was ill in the past sometimes license plates took on meaning somehow, like it was a little personal message on a random passing car. I'm not sure what sort of delusion that was.