@hilljam "Jazz" and "rules" seem like odd bedfellows, and I think there's a larger categorization to music that could be applied: whether the emphasis is on structure or on expression. It reminds me of something Trent Reznor said about being inducted in the Rock and Roll Hall of Fame, on what "rock" even is and that the Hall of Fame can recognize "synth" bands: "It's the spirit of expression and, to me, freedom and no limits to expression. That's my version of what rock means."