Develop a musical composition using the outlined alphabetical depiction of the structure and the provided theme.
X:1
L:1/8
M:6/8
K:D
['dfa gec', 'FGA AB=c']  
X:1
L:1/8
M:6/8
K:D
|: dfa gec | dfa gec | dfd Bge | ced cBA | dfa gec | dfa gec | dfd Bge | TcBc d2 :: FGA AB=c | 
 B^cd cde | dAd eAe | fdf{f} e3 | FGA AB=c | Bcd cde | eag fed | TcBc{c} d3 :|  