From a notes perspective we’re looking at a combination of the G minor pentatonic scale (G Bb C D F), blended with some well chosen chord tones from our implied G7 tonality (G B D F).

We can extend up to a 13th in this way by progressively adding in the non-chord tones of a scale – in theory ... As a reference point, here is a G7 chord. These contain a b7th, which is referred ...