Test

CC#DD#EF

IIm7 → V7(9, 13) → I△7I△7 → VI7(#9, b13) → II-7 → V7(#9, b13)

tonality

II_-7

V₇^{(9, 13)}

I_7

code

D_-7

G₇^{(9, 13)}

C_7

keyboard