Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:2/2
K:G
['G>Bd>B g>ed>B', 'g>ag>e a>ba>e']  
X:1
L:1/8
M:2/2
K:G
 B | G>Bd>B g>ed>B | g>ed>B e>AA>B | G>Bd>B g>ed>B | c<A d>c B>AG :: d | g>ag>e a>ba>e | 
 g>ag>e e>dd>e | g>ag>e a>ba>e | g<e e>g B>A G :|  