The tradition (not always followed) is for clock faces with Roman numerals to use IIII instead of IV. This helps keep people from misreading the sequence “VI V IV” as is appears at the bottom of the dial. (I once played a hidden-object mystery game in which the programmer-artist had mistakenly painted “VI V VI”, showing that such mistakes can happen.)
The tradition (not always followed) is for clock faces with Roman numerals to use IIII instead of IV. This helps keep people from misreading the sequence “VI V IV” as is appears at the bottom of the dial. (I once played a hidden-object mystery game in which the programmer-artist had mistakenly painted “VI V VI”, showing that such mistakes can happen.)