I wrote a parking meter program just to see if I could.
It added time based on the coin inserted, and added different times if it was an American coin or a Canadian coin - both sides of the border here there is a mix of both coins. Canadian coins got different time depending on the exchange rate entered. It also added time for pennies, nickels, dimes, quarters and half dollars depending on the ability of the coin mechanism.
I think I remember a timer triggered a counter counting down, adding coins increased the counter accumulator, accumulator gets to 3 then Warning flag pops up, at 00 the Expired flag pops up.
Plus, just for fun, when the Expired flag output came on another output labeled DETONATOR was energized for 1 second too.