Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/16
Q:1/4=58
M:3/4
K:Bb
['F2 D2', 'B, B,2', '']  
X:1
L:1/16
Q:1/4=58
M:3/4
K:Bb
 F2 D2 D D3 (D C) B,2 | F2 D2 D F3 F2 D2 | F2 D2 D D3 (D C) B,2 | C2 C2 C D3 (D C) C2 || 
[M:2/4] C4 (D C) C2 | B,3 B, (B, F,3) | B, B,2 C B,4 | B,4 C B, B,2 ||[M:3/4] F,2 F,2 F,6 F,2 | 
 F,12 |]  