Chord sequence
B♭7 E♭7 B♭7 E♭7 B♭7 F7 E♭7 B♭7 Cm7 F7
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 Bb major
Chords 9 to 10
Cm7 F7
Over Bb7 · V7/IV
Mode 5 of Major
Over Eb7 · IV7
Mode 4 of Melodic Minor
Over Bb7 · I7
Over F7 · V7
Over Cm7 · ii7
Mode 2 of Major