chor 1 2
chor 2 4
mu 1 2 3
chor 3 10
mu 3 2 4   # cd^2
iv 2 5
mu 1 5 6   # cd^-1
mu 3 6 7
mu 7 4 8
chor 8 2
mu 2 3 9
com 1 9 10
chor 10 4
pwr 3 3 11
mu 11 4 12
chor 12 7