Chord sequence
Fm7 A♯7 F♯m7 B7
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 E major
Chords 1 to 2
Fm7 A#7
Chords 3 to 4
F#m7 B7
Over Fm7 · ♭ii7
Mode 6 of Blues
Over A#7 · V7/vii
Over F#m7 · ii7
Mode 2 of Major
Over B7 · V7
Mode 5 of Major