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:G
['GAB D3', 'dBG A3']  
X:1
L:1/8
M:6/8
K:G
 d | edB GAB | D3 GAB | D3 cBA | AGE GBd | edB GAB | D3 GAB | D3 cBA | AGF G2 :: c | B3 def | 
 gfe dBG | A3 AGA | BAG E3 |1 B3 def | gfe dBG | A3 cBA | AGF G2 :|2 g3 aga | bge dBG | A3 cBA | 
 AGF G2 ||  