I'd never really thought about this before, but it is kind of amazing to think that Giuffre's last Verve date with his quartet — IN PERSON — dates from July 1960. By March of 1961, his new trio with Bley and Swallow is making a very different kind of music. Seems/feels like a fairly rapid "evolution" to me. (Understanding that there's interrupted continuity from some of Giuffre's 50s work to the "3" recordings.)