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
['G>B dG ce g>e', 'g2 g>d ec g>e']  
X:1
L:1/8
M:2/4
K:G
|: B/A/ | G>B dG | ce g>e | dB BA/G/ | Bd/B/ AB/A/ | G>B dG | ce g>e | dg/d/ Bd/B/ | AG G :| f | 
 g2 g>d | ec g>e | dB BA/G/ | Bd/B/ Af | g2 g>d | ec g>e | dg/d/ Bd/B/ | AG Gf | g2 g>d | ec g>e | 
 dB BA/G/ | Bd/B/ AB/A/ | G>B dG | ce g>e | dg/d/ Bd/B/ | AG G ||  