Construct a musical piece that follows the designated lettered structure and integrates the provided motif throughout.
X:1
L:1/8
M:6/8
K:Bb
['D3/2 F/']  
X:1
L:1/8
M:6/8
K:Bb
 D3/2 F/ d c2 B | D3/2 F/ B A3 | E3/2 F/ e d2 c | c B G F3 | D3/2 F/ d c2 B | D3/2 F/ B A2 G | 
 F B e d B2 | c G A B2 z |]  