Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:6/8
K:D
['A3 dAF FGE E2 A Ace ged']  
X:1
L:1/8
M:6/8
K:D
 A3 dAF | FGE E2 A | Ace ged | c3 ecB | A3 dAF | FGE E2 A | Ace ged | cBc dcB :|  