Compose a piece of music by integrating the assigned letter representation and provided tune.
X:1
L:1/8
Q:1/4=120
M:3/4
K:G
['G/Bd/ c>BA>ed>c B>D G3 B A>D F3', 'z z']  
X:1
L:1/8
Q:1/4=120
M:3/4
K:G
 G/Bd/ | c>BA>ed>c | B>D G3 B | A>D F3 A | B>D"^etc" G2 z z z || Bc | dgec'af | gbgdBG | 
"^etc" z z z | z z z |]  