Let me establish a setting for you. It’s a very boring setting. You’re in Lower Manhattan, in the heart of the Financial District. It’s gray outside, or at least you think it is, as being in this part of town doesn’t often involve a lot of being outside. The streets are narrow and buildings crowd the sky, and almost anyone around here is shuttling quickly from point A to point B with their head down. You find yourself in a beige, nondescript basement corridor leading toward the massive Fulton Street subway interchange, when suddenly you’re compelled to double back.