The noise is unmistakable, though it’s heard at fewer and fewer casinos these days. Clank-clank-clank-clank-clank. That’s the sound of money — metal coins hitting a metal tray — signifying ...

Dropping a coin into the slot machine initiates a chain reaction: the weight of the coin depresses a metal pan, which in turn results in the opening of a valve, which in turn allows the water to flow ...