Generate a piece of music.  
X:1
T:Music21 Fragment
C:Music21
L:1/8
M:4/4
I:linebreak $
K:Ab
V:1 treble 
V:1
 E2 | A2 A2 A3 B | c2 c2 c2 Ac | e2 e2 fe dc | B2 Bc{/Bc} !fermata!B2 cd | e3 d c2 AG | %6
 F2 B2 AG FE | A2 A2 A2 Bc |{/de} d2 c2{/Bc} !fermata!B2 cd | e3 d c2 (3Bcd | c2 B2 A2 z2 || %11  