Generate a piece of music.  
X:1
T:Music21 Fragment
C:Music21
L:1/4
M:4/4
I:linebreak $
K:F
V:1 treble 
V:1
 F | F C F A | F2 F A | G3/2 F/ G A | B3 B | A A F A | c2 A F | G G G A/F/ | G3 A/B/ | %9
{/B} A c A F | D C2 F | F D C D | C !fermata!F2 F/>G/ | A3/2 A/ B G | F3/2 G/ A c | A G/F/ G G | %16
 F2 x2 || %17  