Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
M:4/4
K:Bb
['dc B2 .!tenuto!B,2 .!tenuto!B,2 FE DF .!tenuto!B2', '[DB]2 FE DFBF DFBF G2 E2 E2']  
X:1
L:1/8
M:4/4
K:Bb
 dc | B2 .!tenuto!B,2 .!tenuto!B,2 FE | DF .!tenuto!B2 .!tenuto!B2 dB | c2 .C2 .C2 cB | 
 Ac .!tenuto!f2 .!tenuto!f2 ga | (ba).g.f (gf).e.d | (ed).c.B (BA).G.F | GBAc Bdce | 
 d z [DB]2 [DB]2 :| FE | DFBF DFBF | G2 E2 E2 GF | =EGcG EGcG | A2 F2 F2 GA | B z (g g).f.ed | 
 edcB BAGF | GBAc Bdce | d2 B2 [DB]2 :|  