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 B c ||{/A} B{/A} G2 G | F E E F | G2 E F | E D/ C/- C B/ c/ || %8
{/A} B !turn!G2 G | z z z z | z z z z | z z z z || %12  