piano scale
B♭ Dorian
B♭1C2D♭♭3E♭4F5G6A♭♭7
Minor with a natural sixth. The second mode of the major scale.
The same sounds spelled from the other side are A♯ Dorian.
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
B♭WCHD♭WE♭WFWGHA♭WB♭
What is true of it
B♭ Dorian is B♭, C, D♭, E♭, F, G and A♭, and back to B♭.
Its steps are W – H – W – W – W – H – W, where W is a whole step and H a half.
On the same tonic, B♭ natural minor differs from it by exactly one note.
Chords made only of these notes
Found by testing every chord in the catalogue against these 7 sounds, not chosen.