Music can trigger stirring memories of unique experiences — The 1975 Köln Concert, Keith Jarrett, Part 1 (impromptu, live) (Youtube) It’s not a song, so, technically, it doesn’t belong here. But it’s the inspiration for this reminiscence. It is a strikingly glorious, live, improvisational jazz piano concert by a prodigy of his time, of whom, sadly, I knew…