Free Font: War
Free Font: War
The function of a flag.
A hasty but not necessarily absurd answer would be the marking of territory and the way it is sometimes acquired: war.
WAR is a typeface which deconstructs all the "official" countries' flags (2006) to allow a random redesign of your own country. If you are a tyran and wonder what signs your flag should deploy, type the name of your beloved wife / husband / child or favourite dog then change the typeface to WAR. It will provide you with the symbols to signify your supremacy.