"I play the McCann Duet. If I only played the tune, what exactly would my left hand be doing?"

Waving ? Making obscure* gestures ? Being musically redundant ??

*spelling mistake ??

"(McCann Duet.....look it up)"

Here you go!

And just in case WAV should come back on your spelling of the name,Ralphie, perhaps it should be pointed out by a nerd like me that for years the name was spelled the way you do, whereas in recent years the more recognised spelling adopted is the one in the article - which it is now known is the way the revered Professor Maccann spelled his name. A rose by any other name, and all that ... still a great instrument however you spell it. Not England's National musical instrument ... but I suppose actually an English instrument (unless Maccann proves to have been Polish, Scottish or Irish ????)