Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:4/4
K:D
['DFAF (3DEF A,2 EGAG (3EFG A,E FAdA', 'ec (3ABA EAce fd (3ABA FAdf']  
X:1
L:1/8
M:4/4
K:D
 DFAF (3DEF A,2 | EGAG (3EFG A,E | FAdA GBeB | Adfd (3cBA (3GFE | DFAF (3DEF A,2 | EGAG (3EFG A,E | 
 FAdA Ggec |1 dedc dFFE :|2 dedc dfgf || ec (3ABA EAce | fd (3ABA FAdf | (3gag fg efdf | 
 (3efe (3dcB ABcd | ec (3ABA EAce | fd (3ABA FAdf | gbag fdec | dedc dfgf | ec (3ABA EAce | 
 fd (3ABA FAdf | (3gag fg efdf | (3efe fg a2 (3Ace | aece (3Ace (3gfe | fdAF (3DFA (3dfa | 
 gbag fdec | dedc d2 d2 ||  