piano scale
G whole tone
G1A2B3C♯♯4D♯♯5E♯♯6
Six notes, every step a whole one. There are only two of these scales in all, and every note can be heard as the tonic.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
GWAWBWC♯WD♯WE♯WG
What is true of it
G whole tone is G, A, B, C♯, D♯ and E♯, and back to G.
Its steps are W – W – W – W – W – W, where W is a whole step and H a half.
Chords made only of these notes
Found by testing every chord in the catalogue against these 6 sounds, not chosen.