Chord sequence
G7 C7 G7 C7 G7 D7 C7 G7 A♭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 G major
Over G7 · V7/IV
Mode 5 of Major
Over C7 · IV7
Mode 4 of Melodic Minor
Over G7 · I7
Over D7 · V7
Over Ab7 · subV7