Generate a piece of music. It is monophony.  
X:1
T:Music21 Fragment
C:Music21
L:1/8
Q:1/4=68
M:2/4
I:linebreak $
K:F
V:1 treble 
V:1
 AA AA | c3 z | BB G z | AA F z | AA AA | c2 !fermata!z3/2 B/ | Ac BG | F3 z | d2 c>A | %9
 B/A/G/F/ EC | FF GG | A2 z A/B/ | c2 f2 | c2 z B | A/A/A BG | F3 z || %16  