Compose melodious music utilizing the prescribed letter representation and integrating the given thematic element.
X:1
L:1/8
M:4/4
K:G
['ga b2']  
X:1
L:1/8
M:4/4
K:G
 g2 G2 bc d2 | ga b2 ag f2 | ga b2 gd B2 | cA F2 G4 | GA G2 bc d2 | ga b2 ag f2 | ga b2 gd B2 | 
 cA F2 G4 ||  