Create a musical composition employing the given alphabetic structure and melodic theme.
X:1
L:1/4
M:3/4
K:G
['D G2 B']  
X:1
L:1/4
M:3/4
K:G
 D | G2 B | G2 D | E2 F | G2 D | G2 B | A2 D | G F E | D2 |]  