Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:6/8
K:G
['G G']  
X:1
L:1/8
M:6/8
K:G
 D | G G G G2 A | B B B (Bd) d | d g d d B G | A2 A A2 d | d e f g (dB) | e d B A D D | 
 G G G (GB) d | e2 f g3 |[M:3/8] g2 e |[M:6/8] e d B d c A | (G3 G2) |]  