Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:12/8
K:D
['A2 D FED F2 A A2 f', 'f2 f']  
X:1
L:1/8
M:12/8
K:D
 dB | A2 D FED F2 A A2 f | gfe fed e2 d B2 d | A2 D FED F2 A A2 f | a2 f e2 f d3 d2 :| A | 
 d2 e f2 a a2 f fef | g3 faf e2 d BAB | d2 e f2 f gfe f2 f | a2 f e2 f d3 d2 A | 
 d2 e f2 f gfe f2 f | gfe fed e2 d BAB | d2 e f2 f gfe f2 f | a2 f e2 f d3 d2 ||  