If the harp is chromatic (it can play in any key), then if the harpist plays one tune in G and then plays the next tune in Bb... you will have to change whistles even though they don't need to change harps. (I don't know anything about harps specifically, but this would apply to all chromatic instruments)
Those irritated by grain of sand best avoid beach.
-Strumelia proverb c.1990
updated by @strumelia: 08/04/21 10:41:12AM