Carol C, I was listening to a song called Heart (I think) by Mary Coghlan on the radio, which made me think of you. Not sure that I'd heard the song before but it has an accordion playing a break in the piece, which was largely pentatonic (with a few chromatic bits) that's as good an example as any of what the web article is all about. It could equally have been guitar, violin, harmonica or sax taking the lead.

Regards, John