Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:2/4
K:G
['BG D>D Ec cA/B/', 'd/ ee dd B3 B/c/ d>e dB']  
X:1
L:1/8
M:2/4
K:G
|: BG D>D | Ec cA/B/ | cE F>E | Dd d/e/d/c/ | BG D>D | Ec cA/B/ | c/B/A/G/ F/D/E/F/ |1 GB Gd/c/ :|2 
 GB GB/d/ |: g2 f2 | c7/2 d/ | ee dd | B3 B/c/ | d>e dB | A2 AB/A/ |1 G>A Bc | d2 de/f/ :|2 Gg fa | 
 g2 g ||  