Fluorescent lights

If one looks closely, it becomes apparent that there is no way out of the bar area, as the three walls of the counter form a triangle that traps the attendant. It is also notable that the diner has no visible door leading to the outside, which illustrates the idea of confinement and entrapment. Hopper denied that he had intended to communicate this in Nighthawks, but he admitted that "unconsciously, probably, I was painting the loneliness of a large city."