Chord sequence
Cmaj7 D♭dim7 Dm7 D♭7
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 C major
Over Cmaj7 · Imaj7
The major scale and its modes are the most commonly used scales in western music.
Over Dbdim7 · ♭ii°7
Mode 7 of Harmonic Minor
Over Dm7 · ii7
Mode 2 of Major
Over Db7 · subV7
Mode 4 of Melodic Minor