why do some roman clocks still write number four as IIII instead of IV

The use of "IIII" instead of "IV" for the number four on some Roman numeral clocks is based on a few factors:

1. Elegance and Symmetry: Clock faces are typically designed with a circular layout. To maintain symmetry, using "IIII" instead of "IV" ensures that the numerals are distributed evenly around the clock face. For instance, having "IIII" at 12 o'clock and "IV" at 4 o'clock would create an asymmetry.

2. Traditional Use: Historically, in certain contexts, "IIII" was used to represent four, particularly in legal and religious documents. The practice of using "IIII" for four on clocks is a continuation of this tradition.

3. Misunderstanding: Some believe that the use of "IIII" is due to a misunderstanding of Roman numerals, where people might think that using "IV" could be confusing because it looks like two separate numerals ("V" minus one "I"). However, this is not actually a reason behind the practice, as Roman numerals are well established and understood by those familiar with them.

4. Custom and Preference: Ultimately, the choice between "IIII" and "IV" on a clock can come down to custom or preference for the designer or manufacturer of the clock. There isn't a strictly enforced rule, and both representations are correct.

It's important to note that while "IIII" is often seen on analog clocks, digital clocks and most other modern uses of Roman numerals typically display the number as "IV."