Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:4/4
K:G
['d2 e2']  
X:1
L:1/8
M:4/4
K:G
 G3 A B2 d2 | A2 BA G2 GA | B3 c d2 e2 | c2 dc B4 | G3 A B2 d2 | A2 BA G2 GA | B3 c d2 e2 | 
 c2 dc B4 | d2 d2 e2 ed | c2 ce d4 | B2 Bd c4 | B2 B2 A4 | B2 B2 c2 ce | d2 dc B2 z2 |]  