A: Excuse me! I need a ticket.
B: You owe me a dollar.
A: I already put one in!
B: Yes, and you owe me another.
A: The counter says fare is one dollar!
B: The fare counter tells how much money you've inserted.
A: I don't understand.
B: It reads one dollar because you put in a dollar.
A: How do I know I've paid the fare?
B: The counter will go back to zero.
A: Oh, I see what you mean.
B: Now that you've paid your two dollars, here's your ticket.