WAG region colors?

[gymgal]

How do the regions pick their colors and how long do they keep them?

 

[Gymmonkeymomma]

Colors change every 4 years. No idea how they are chosen though.

 

[fuzi]

Pretty sure they are assigned by USAG. Do they change every 4 years? I thought it was more like every 8, or however long GK still had materials in those colors.