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
 z z z z | z z z z | z z z z | z z C C || !turn!F2 E F | G2 B B | c !turn!c2 B | B2 G2 || %8
{/^F} G2{/G} E =F | G2 E F | E2 C C- | C D C C || %12  