there are times of mine, that i think of, when set off by a certain quality of light, or some smell and aroma, or movement..being in a vehicle, on a highway in and around nyc, especially if i am not the one driving, and having the streetlight in their shroud of yellow light, deepening its own shadows, outlining the garbage. pavement, guardrails, the way to go..and if the window is open or slightly open, the exhaust from diesel trucks, the cars, the water, old concrete, decay..rats..