the number four in some old roman clocks is still usually written as IIII instead of IV

Indeed, you are correct. In the context of traditional Roman sundials and some old clock faces, the numeral for four is often represented as "IIII" rather than "IV." This practice has historical roots and is more about tradition and aesthetics rather than logical notation.

1. Aesthetic Consistency: On clock faces, the use of "IIII" for four aligns with a pattern where each numeral is symmetrical and balanced, visually pleasing, and matches the appearance of other numerals that are made up of a single character repeated (like "V" for five, "VI" for six, etc.).

2. Historical Tradition: The "IIII" notation has been used for centuries on sundials and other timekeeping devices. It's less about mathematical logic in subtraction (which is the rationale behind "IV") and more about maintaining a consistent appearance across all numerals.

3. Error or Misunderstanding: Some theories suggest this might have started as an error or misunderstanding but became a standard due to its widespread use over time.

Despite being atypical compared to the standard Roman numeral system, "IIII" for the number four is widely accepted in the context of antique timepieces and is considered charming and characteristic of older styles. Modern clocks and formal Roman numeral usage still predominantly use "IV."