There is an urban legend that the bloke who fired the One-O-Clock Gun from Edinburgh Castle timed it by looking at the clock on the corner of Binns (department store at the end of Princes Street) with his binoculars. But the Binns employee in charge of setting the clock timed it by listening for the One-O-Clock Gun.

Anybody who's ever applied for a state benefit or official permission for something will have had much nastier experiences of circularity.