Butler is awesome, and it has always sounded to me like, of the drummers most influenced by African music, he has really taken the approach to a more sonic level (apart, that is, from purely rhythmic). I'm actually blanking on it now, but there is a particularly interesting non-isometric solo on that Elmo Hope Trio record that really shows this to be the case - not to mention his work with Trane on Kulu Se Mama.