Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:9/8
K:G
['g2 B BAB', 'e fed']  
X:1
L:1/8
M:9/8
K:G
 EDE e2 B G2 B | A3 A2 G A2 B | EDE G2 B e2 f |1 gfe fed B3 :|2 gfe fed e2 f |: g2 B BAB g2 e | 
 f2 A AFA f2 d |1 g2 B BAB g2 e | fed afd gfe :|2 g2 e fed efg | BcB AGF E3 |]  