Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:6/8
K:D
['', 'CA,A, EA,A, DEF GFE FGA BGE', 'DFA dAF AFD FGA GGB BGE', 'A DFA dAF AFD FGA GGB BGE']  
X:1
L:1/8
M:6/8
K:D
 DED |: CA,A, EA,A, | DEF GFE | FGA BGE | E{A}ED CB,A, | CA,A, EA,A, | DEF GFE | FGA BGE | 
 EDC D2 D :| DFA dAF | AFD FGA | GGB BGE | EED CB,A, | DFA dAF | AFD FGA | GGB BGE | EDC D2 A || 
 DFA dAF | AFD FGA | GGB BGE | EED CB,A, | DCD EDE | FEF GFG | FGA BGE | EDC D2{E} D ||  