Develop a musical composition using the outlined alphabetical depiction of the structure and the provided theme.
X:1
L:1/8
Q:1/4=104
M:6/8
K:G
['BGG DGG BGB dcB', 'G2 g/a/ bgg dgg bgb bag afd']  
X:1
L:1/8
Q:1/4=104
M:6/8
K:G
"^Moderato" d/c/ | BGG DGG | BGB dcB | cAA EAA | cAc edc | BGG DGG | BGB dcB | cBc Add | BGG G2 || 
 g/a/ | bgg dgg | bgb bag | afd Adf | fdf agf | egg dgg | cgg Bgg | cbc Add | BGG G2 ||  