And while it's not a formal rules requirement, make sure that whatever you use can't be mistaken for a
different number. Here are some suggestions towards that:
- All of your openings and space between the digits should also be at as wide as the stroke width (or nearly so), so that a 5 is not read as a 6 or a 3, 5, 6, or 9 as an 8.
- Include an opening in your 4 and a curved tail on your 9 to keep them from being mistaken for each other.
- If you have a top serif on your 1, make it not much bigger than the stroke width, and that the top bar on your 7 is well over twice the stroke width, so they can't be confused.