OK, well with just about everything that more than three people have an interest in and it becomes 'a thing', it gets given an -ology for its study and -ography for its practice. For those who are interested in flags, someone has allocated the word 'vexill' to them. Presumably because it will be rather funny listening to them trying to pronounce 'vexillology' late on into their Christmas party.

Anyway some vexillologists got together and decided that these 5 principles should apply to any flag design:

1. Keep it simple - a child should be able to reproduce the flag from memory.
2. Use meaningful symbols - the symbols, shapes and colours of a flag should be relevant to what they represent.
3. Use 2 or 3 basic colours - the colours should contrast well and come from a basic colour pallette (whatever that means)
4. No lettering or seals - flags should contain no writing and should not have an organisational/guild seal or coat of arms. I don't know if the animal is included here. (Nor the 1990s soul singer)
5. Be distinctive or be related - Flags should be unique, but nations that are connected can have similarities.
6. There is no number 6.