Generate a piece of music.  
X:1
T:Music21 Fragment
C:Music21
L:1/4
M:none
I:linebreak $
K:none
V:1 treble 
V:1
{/B,} C{/C} F E G- | G G B B | c B/ A/ G2 | E F G F || E2 C2 | C C B,2 | G,2 B, B, | C2 C F || %8
{/F} E3 F | E F E2 | E F !turn!G2 | F E2 C || %12  