Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:4/4
K:G
['B2 GB AGEG DGGF', '(3ded Bd gdBd']  
X:1
L:1/8
M:4/4
K:G
|: GA | B2 GB AGEG | DGGF G2 AB | c2 Ac BAGF | EAAG FDGA | B2 GB AGEG | DGGF GABc | 
 (3ded Bd gdBd |1 cAFA G2 :|2 cAFA GABc |: (3ded Bd gdBd | (3ded Bd gd(3Bcd | e2 ce agfe | 
 defg agfe | (3ded Bd gdBd | (3ded Bd gdBd | c2 Ac BAGB |1 AGFA GABc :|2 AGFA G2 ||  