In unison the class said "What?..." but the instructor was unfazed. "That's our local homeless guy," he explained. "He often comes into these rooms and covers the board with figures." I made sure to get these shots before they were erased, wondering if we had another John Nash.
Of course it's more likely that the man is just sick and these numbers are gibberish. (For the record, there's no way to tell just from finding numbers whether the person is schizophrenic.) I actually emailed the pictures to a cosmologist friend* to see if they meant anything (they reminded me of quantum numbers) but my friend said there was no order to them that he could see. Still, it's tempting to look for patterns on the principle that, if there is indeed any method to this madness, we could get to the concepts inductively. Once at a party, as a game I decided to play what appeared to be a single-player solitaire-like game. I moved the cards around randomly but with great apparent concentration (I don't even know the rules for real solitaire) and soon enough, someone started watching. "I think I have the rules figured out," he offered after a few minutes. (Given the limited input, he may well have.)
Beyond problems of induction, there remains the question of why someone with mental health issues would develop a habit like this in the first place. My best guess is that, since he's homeless on a university campus where social status accords with intelligence (or at least proxy indicators of it), by writing opaque patterns of numbers he can maintain the delusion that he's a misunderstood genius, at least as long as he's writing his number-patterns in empty rooms where they aren't critiqued by people with real math abilities. (A similar strategy would be to write a cognitive philosophy blog with few readers.)
A more interesting possibility is that by finding a way to occupy his attention with a task requiring high concentration and that uses non-diseased parts of his brain, this person has found a way to quell the other constant disturbances to his thinking and can gain himself a moment of peace. Of course this is speculation, but if it hasn't already been asked, this might point the way to novel therapeutic approaches.
*Speaking of status, please note the casual way I refer to my cosmologist friend, which means that I'm cool.