Generate a piece of music. It is monophony.  
X:1
T:Music21 Fragment
C:Music21
L:1/16
Q:1/4=68
M:2/4
I:linebreak $
K:C
V:1 treble 
V:1
 C2 | C2E2 GGcc | BcdB G2 z B | cBcG AGFE | E2DC D2 z C | C2E2 GGcc | BcdB G2 z B | cBcG AGFE | %8
 E2D2 D2 z2 | G6 G2 | e4 c4 | A2A^G ABcA | =G2E2 z4 | CCEE GGcc | BcdB G2 z G | c2GG GAGF | %16
 E2C2 z4 || %17  