piano scale
D♭ diminished (whole–half)
Eight notes alternating whole step and half step. Symmetrical, so it repeats every minor third.
The same sounds spelled from the other side are C♯ diminished (whole–half).
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
What is true of it
D♭ diminished (whole–half) is D♭, E♭, F♭, G♭, A♭♭, B♭♭, B♭ and C, and back to D♭.
Its steps are W – H – W – H – W – H – W – H, where W is a whole step and H a half.
Written correctly it needs 9 alterations, A♭♭ and B♭♭ among them. That is what the letters force, and it is also why nobody writes music in this key: the same notes spelled from the other side are easier to read.
Chords made only of these notes
Found by testing every chord in the catalogue against these 8 sounds, not chosen.
Other scales on D♭
C dim W-HD dim W-HD♯ dim W-HE♭ dim W-HE dim W-HF dim W-HF♯ dim W-HG♭ dim W-Hall 374