Compose a piece of music by integrating the assigned letter representation and provided tune.
X:1
L:1/8
M:4/4
K:Bb
['B3 c d2 d2 e2 c2', 'f2 b2 e2 c2 d4', '[B,DG]2 F2 DFBd FBdf e2 c2 d4', '[Gc]2 [Ac]2 Bc [Fd]2']  
X:1
L:1/8
M:4/4
K:Bb
 FG | B3 c d2 d2 | e2 c2 d4 | [Gd]2 [Gc]2 [Ac]2 Bc | [Fd]2 [Ac]2 [Fc]2 [GB]G | B3 c d2 d2 | 
 e2 c2 d3 c | [GB]2 [B,G]4 FG | [DB]2 [B,DG]2 [B,DG]2 :: df | g2 b2 f2 b2 | e2 c2 d4 | 
 [Gd]2 [Gc]2 [Ac]2 [FB]c | [Fd]2 [Fc]2 [Ac]2 [Bf]2 | g2 bg f2 b2 | e2 c2 d4 | [GB]2 [B,G]4 FG | 
 D2 B2 [B,DG]2 [B,DG]2 :: F2 | DFBd FBdf | e2 c2 d4 | [Gd]2 [Gc]2 [Ac]2 [FB]c | 
 [Fd]2 [Fc]2 [Ac][ce][Bd][Ac] | Bdfd Bdfb |{f} e2 dc d3 c | [GB]2 [B,G]4 FG | 
 [DB]2 [B,DG]2 [B,DG]2 :: f2 | gbab dbfd | E2 c2 d4 | [Gd]2 [Gc]2 [Ac]2 Bc | [Fd]2 [Gc]2 [Ac]2 Bc | 
 [Fd]2 [Fc]2 [Ac]2 [Bf]2 | gabg fgab |{f} e2 dc dedc | [GB]2 [B,G]2 [B,G]2 FG | 
 [DB]2 [B,DG]2 [B,DG]2 :|  