Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:12/8
K:G
['DFE DFF B2 A DFE D3']  
X:1
L:1/8
M:12/8
K:G
"D" A3 AGF |"A" EFG"D" A3 |"G" B3 BAA |"D" dAA"G" G2 F |"D" DFE DFF |"D" FED"G" B2 A |"D" DFE D3 | 
"A" EDE"D" F2 D |"D" DFE DFF |"D" FED"G" B2 A |"D" DFE D3 |"A" EDE"D" D3 :|"G" BAB dBd | 
"G" dcB"D" c2 A |"D" AGA cAc |"D" cBA"G" B2 G |"G" BAB"Em" EFG |"G" GAB"D" d2 c |"C" cdc"G" BcB | 
"D" ABA"G" G3 :|  