Chord sequence
A♭m7 Am7 A♭m7
In every key
Four-note rootless voicings in their two forms, with the 3rd or the 7th on the bottom, played over the root.
Heard in Ab minor
All the chords
A 32-bar AABA form with one minor 7th chord to each section: eight bars of Dorian on i, and a bridge a half step higher.
Over Abm7 · i7
Mode 2 of Major
Over Am7 · ?