Why do I think that?
Because I heard someone yelling repetitively in the street, below my 13th floor apartment. One person, yelling loudly, some sort of chant. I could not hear the words.
Ah, I thought and came up with a new rule: if it’s a lot of people yelling repetitively, it’s a protest. If it’s only one person, it’s a psychotic episode. That is, normal New York.