Construct a musical piece that follows the designated lettered structure and integrates the provided motif throughout.
X:1
L:1/8
M:3/4
K:Bb
['b2 z', 'G2 F2', 'G2 F3', 'b2 z a']  
X:1
L:1/8
M:3/4
K:Bb
 b2 z a ||"Bb6" g6- | g2{g} f3 d |"Bb"{c} B6- | B2 G2 F2 | [df]2 [_df]2 [cf]2 | 
"Bdim" [=Bf]2 [cf]2 [df]2 |"F7" [ef]2 [df]2 [ef]2- | [ef]2 b3 a | g6- | g2{fg} [Af]2 [Ge]2 | 
 [EA]6- | [EA]2 G2 F2 | (3Af[cf][Af] [cf]4 | (3[Af][_df][Af] [_df]4 |"Bb" [=df]6- [df]2 b2 z a | 
"Bb6" g6- | g2{a} f3 d |"Bb" B6- | BB G2 F2 |"G7" [=Bg]6 |"G7" [Fd]4 [^Fd]2 ||"Cm" [Ge]6- | 
 [Ge]2 g2 (a2 | b)c' bg ec |"A7" a4 g2 |"Bb"{a} fg fd BF |"G7" [Ge]4 [Fd]2 |"C9" [=Ed]3{cd} c =Bc | 
"F7" d3 c AF |"Bb"{Bc} BA cB FD |"Bb7" C2 B,2 =B,2 ||[K:Eb]"Eb" C4 G2- | G2 C2 =B,2 | =B, _B,4- | 
 B,4 B,=B, | C4 E2 | G2 B3 c |"Bb7"{c} B6- | B2 A3 B | A2 G2 F2 |"Bbdim" =E4 F2 | 
"Bb6" G3{AG} ^F GB |"Bb7" A6 |{=EF} G2 F3 =E |"Bb7" G2 F3 _E | (3DFE D2 C2 |"Eb" B,2 B,2 =B,2 | 
 C4 G2- | G2 (C2 B,2) | _B,6- | B,2{D} ^F2 G2 |"C7" [G,=Ec]6 | [B,G]4 [=B,G]2 |"Fm" [CA]6- | 
 [CA]2 C2 D2 |"Ab" E3{FE} D E=E |"Abm6" F4 _EF |"Eb" G2 B3{cB} A |"C7" A4 c2 |"F7" c6 | 
"Bb" [A,D]6 |"Eb" E4"E" =E2 |"F7" F2 ||[K:Bb] b2 z a ||"Bb6" [dg]6- | [dg]2 [Bf]2 [Fd]2 | 
"Bb" [DB]6- | [DB]2 G2 F2 | [df]2 [_df]2 [cf]2 |"Bdim" [=Bf]2 [cf]2 [df]2 |"F7" [ef]6- | 
 [ef]2 b2 z a | g6- | g2{g} [Af]2 [Ge]2 | E A6 |] | [EA]2 G2 F2 |"F7" (3[Af][cf][Af] [cf]4 | 
"F+" (3[Af][_df][Af] [_df]4 |"Bb" =d6 f6- | [df]2 b2 z a |"Gb6" g6- | g2{a} f2 d2 |"Bb" B6- | 
 B2 G2 F2 |"G7" [D=Bg]6 | [Fd]4 [^Fd]2 |"Cm" [Ge]6- | [Ge]2 g2 a2 |"Eb" bc' bg ec | 
"A7" [^ca]4{f} g2 |"Bb" fg{f} fd BF |"G7" [Ge]4 [Fd]2 |"C9" [=Ed]2{cd} c =Bc |"F7" d3 c AF | 
"Bb" BF dB fd | b2 ||  