Why do some analog clocks with Roman numerals have '4' as 'IV,' while others have 'IIII'? This is one of those questions where no one seems to have a definitive answer, and probably no one ever will.

Roman numerals are ... One of those is in time keeping, in which many clocks use the classical numerals instead of the more popular Arabic replacements. [Nicola]’s clock does too, albeit ...