Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:2/4
K:G
['GBdg fe/d/ c2', 'G4 AA BB c/d/c/B/ A2 BB ce']  
X:1
L:1/8
M:2/4
K:G
 GBdg | fe/d/ c2 | Bd Bd | A/G/A/B/ A2 | GBdg | fe/d/ c2 | BB/c/ AA/B/ | G4 :: AA BB | 
 c/d/c/B/ A2 | BB ce | ed dB | GBdg | fe/d/ c2 | BB/c/ AA/B/ | G4 :|  