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
['B2 c d2 d']  
X:1
L:1/8
M:6/8
K:G
 B2 c | d2 d c2 B | A3 B2 A | G3 A2 F | G3 B2 c | d2 d | ^c2 d | e2 d ^c2 d |]  