Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:4/4
K:C
['DED DED', 'FDF GEA']  
X:1
L:1/8
M:4/4
K:C
 e!p!ace G D e |[M:6/8][K:G] fed[Q:1/8=160]"^D modal" .D2 d cAG | F3 GEA | DGE EFD | AGE EFD | 
 D2 d cAc | dcA GEA | DED DED | DED DED :| ABA GAG | FDF GEA | DGE EFD | AGE EFD | A/B/cA dAG | 
 FDF GEA | DED DED | DED DED :|  