I have this watch with a zero at the top instead of a 12. I was bragging to my girlfriend that this was actually the correct way of doing it, modular arithmetic blah blah.

She said that in the past people didn't have watches and listened out for the village bells to get a rough idea of what time it was and when to have lunch.

I had to admit that striking zero o'clock on the bells would not be effective so maybe the 12 makes sense after all.

But what does it mean?