Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/16
M:2/4
K:D
['', '(3A,B,C D2DE FAA2 Be2f edBc dcdB AFdB', 'a2fd bage cBcA defg afed Bdce']  
X:1
L:1/16
M:2/4
K:D
 (3A,B,C |: D2DE FAA2 | Be2f edBc | dcdB AFdB |1 AGFE DCB,A, :|2 AGEF D2 |: A2 | defd a2fd | 
 bage cBcA | defg afed | Bdce d2 :|  