Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:2/2
K:A
['A2 AcBA', 'defg aefd cABG :|2 GABc defg a2({b}']  
X:1
L:1/8
M:2/2
K:A
 (3(efg) | a2 A2 AcBA | E2 A2 AcBA |1 F2 B2 BcBA | GABc defg :|2 GABc defg | aece A2 |]: (3(BAG) | 
 A2 a2 A3 B | B2 b2 B3 A |1 GABc defg | aefd cABG :|2 GABc defg | a2({b} ag) a2 |]  