The Bernsteing "America" example uses BOTH because of the Time Signature changes.

One bar of each in succession.


Really not a good example for teaching somebody the basics, eh?


Just serves to further confuse IMO.

The fellow asking about the basics of Primary Colors just wants ROY G BIV, not folks going off on how many of the various hues may be recognizable by the human eye or possibly worse yet, how many YOU can see as versus others... KISS



--Mac