Generate a piece of music.  
X:1
T:Music21 Fragment
C:Music21
L:1/4
M:none
I:linebreak $
K:none
V:1 treble 
V:1
 G G G{/c} B | B2 B2 | c2 c2 | c d c2 ||{/B} c2 c c | B B G G | G G B2 | c B G2 ||{/G} E F G G | %9
 c B !turn!G2 | G2 E F | E !turn!C2 B, || %12  