Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
Q:3/8=120
M:6/8
K:Amin
['A2 B c2 d ecA', 'B c2']  
X:1
L:1/8
Q:3/8=120
M:6/8
K:Amin
|: E | A2 B c2 d | ecA ecA | G2 A B2 c | ded dBG | A2 B c2 d | ecA Bcd | efe dcB | A3- A2 :| A | 
 EAA A2 B | c2 B c2 A | G3- G2 E | G3- G2 A | EAA A2 B | c2 B c2 d | e3- e2 c | e3- e2 c | 
 eee edc | d2 d d2 B | c2 c cBA | B2 B Bcd | e3 d3 | c3 B3 | EAA A2 ^G | A3- A2 |]  