Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
M:6/8
K:G
['', 'G2 B BAB', 'g3 bgd']  
X:1
L:1/8
M:6/8
K:G
 |: D | G2 B BAB | gdB gdB | G2 B BAB | AFD AFD | G2 B BAB | gdB gdB | ABB dBB | cAF G2 :: (3Bcd | 
 g3 bgd | g3 bgd | f3 afd | fag fed | g3 bgd | g3 bgd | ABB dBB | cAF G2 :|  