Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:2/2
K:D
['f2 ec', 'f2 ec']  
X:1
L:1/8
M:2/2
K:D
 AG | FDDD DFA=c | BGGG G2 ed | cAAA Aceg |1 f2 ec dB :|2 f2 ec d2 ef |: gagf g2 b2 | abaf d2 fa | 
 gece Aceg |1 f2 ec d2 ef :|2 f2 ec dB ||  