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
{/^F} G2 c c | c2 c c | c2 c c- | c c d c ||{/B} c{/d} c B2 | G G B B | c B/ A/ ^F G | E =F G F || %8
 E E{/C} B, C | B, C E F | G B c2 | c e B c || B3 G | E E E/ F/ G/ A/ | F E D/ C/ C | z z z z || %16  