Ball tally clocks

A relative gave me a ball tally clock for Christmas and now my office percolates to the rattle of steel balls marking the advance of time. It sort of sounds like the servomotors inside a video cassette player or sheet printer and it reminds me of what the really old iron must of sounded like when it attempted to extract pi to a thousand decimal places. Some people call these clocks ball clocks but I don’t think that’s accurate. It’s better to say ball tally clock since the balls aren’t really part of the timing mechanism. All they do is tally the minutes and hours; they are just a display mechanism. They are no more essential to the measurement of time then the little wooden birds are to cuckoo clocks. Even so, ball tally clocks are deceptively simple. It turns out that they are not always easy to represent programmatically. After giving this gift to me, my relative and I discussed what sort of life cycle a marked ball would have in the mechanism and would it depend on its position. To our annoyance we discovered that my ball tally clock introduces some chaos on the finally tally tray, where the trigger ball might insert itself randomly into the tally balls.

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