Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
Q:1/4=120
M:2/2
K:Bb
['BA B2 B,2 B,2 (FE) DF B2', 'B2 FE DFBF DFBF G2 E2 E2']  
X:1
L:1/8
Q:1/4=120
M:2/2
K:Bb
 BA | B2 B,2 B,2 (FE) | DF B2 B2 (dB) | c2 C2 C2 (cB) | Ac f2 f2 ga | bagf gfed | edcB BAGF | 
 GBAc Bdce | d2 B2 B2 :: FE | DFBF DFBF | G2 E2 E2 (GF) | =EGcG EGcG | A2 F2 F2 ed | e2 g2 gfed | 
 edcB BAGF | GBAc Bdce | d2 [BD]2 [BD]2 :|  