piano scale
D♭ whole tone
D♭1E♭2F3G♯4A♯5B♯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.
The same sounds spelled from the other side are C♯ whole tone.
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
D♭WE♭WFWGWAWBWD♭
What is true of it
D♭ whole tone is D♭, E♭, F, G, A and B, and back to D♭.
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.