Some clocks allow to set a single, fixed period after which a time signal is given and the period restarts.
This is claimed to be one way to control time in ancient games.
Q: However, I assume in this case that various phases would be defined: e.g.
- a first phase that ends after 30 min. (or after X days)
- then, every 30 sec. a signal is given
Q: I assume that the player had to put a stone before the gong went.