Parking in Seattle

I found an interesting parking system in Seattle. There is a box which has a lot of slits and each of them is allotted a number. There is no electronic system nor mechanical device. It is just a box locked firmly. When we park a car, we just insert coins or bills through the slit which has the same number as the parking lot we have just parked our cars. If we parked without paying, our car is to be towed away. That's it. Very simple and primitive. I have never seen it of course in Tokyo and even in Vancouver. I guess Seattle is such an old city that it still has a lot of classic system. Anyway, this system is effective only at night, and in the day time, an attendant is on duty to manage the parking lot.