Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/4
M:6/4
K:D
['a2 a a2 g f2 e d3/2', 'd e2']  
X:1
L:1/4
M:6/4
K:D
 a2 a a2 g | f2 e d3/2 e/ f | e2 A B2 ^c |1 d6 :|2 d3- d2 |: d | c2 B c2 d | e3/2 f/ e A2 f | 
 e2 d e2 f | g3- g2 a | f3/2 e/ d e2 A | f3/2 e/ f g2 f | e3/2 d/ c B2 A |1 A3- A2 :|2 A6 ||  