I don’t see how your example is ‘funny’. That’s what you expect to get. -5² is -25. (-5)² = 25.

(This doesn’t consider the separator) Cyan - DD/MM/YY Magenta - MM/DD/YY Yellow - YY/MM/DD The other ones are mixes of those two colors, so e.g. the US is MM/DD/YY and YY/MM/DD (apparently).

Also just noticed I didn’t attribute this picture, I’ll edit my comment.

Glad I can count my own country, Lithuania, among the enlightened.

EDIT: Source of the picture: https://en.m.wikipedia.org/wiki/File:Date_format_by_country_NEW.svg