Generate a piece of music.  
X:1
T:Music21 Fragment
C:Music21
L:1/8
M:3/4
I:linebreak $
K:F
V:1 treble 
V:1
 D/C/ C/D/ | F2 F2 GA | d2 c3/2 B/ A G/F/ | A2 (3ABA GC | (3CD_E F3/2 =E/ D/C/ C/D/ | F2 F2 GA | %6
 c2 A3/2 c/ d3/2 c/ | d>c A A/G/ A/G/F/D/ | F2 F2 x2 |[K:C][M:2/4] d3/2 c/ d d | G>F D C | %11
 (3DEF c =B | A<G F z | c2 (3def | g2 (3fed | cd (3FGA | G>F G z | %17  