talking about the half step playing.what trane did was play a dim half whole over a dom 7th chord. there are only 3 half whole dim scales that cover 12 keys.ie d d# f f#g a a# b c.......the d hw f hw g hw and the Bb half hole are the same.4x3 = 12. its weard but that is the world of trane.play these scales over a dom 7thh chord. tommy lee walker harp and sax macon ga.