G diminished (half–whole)

G1A♭♭2B♭♭3B3C♯♯4D5E6F♭7

The same eight notes started a half step earlier: the scale that spells a dominant seventh with a flat ninth and a sharp ninth at once.

Written out

Fig. 2 · G diminished (half–whole), ascending

Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.

GHA♭WB♭HBWC♯HDWEHFWG

G diminished (half–whole) is G, A♭, B♭, B, C♯, D, E and F, and back to G.

Its steps are H – W – H – W – H – W – H – W, where W is a whole step and H a half.

Across the first twelve frets of the guitar its notes fall in 53 places, which is what makes a scale a shape rather than a list.

Found by testing every chord in the catalogue against these 8 sounds, not chosen.