Craft a musical piece in accordance with the designated structure and theme.
X:1
L:1/8
M:4/4
K:Bb
['D>C C<D', 'd>Bf>B g>Bf>B d<bf<g d<fc<d'  
X:1
L:1/8
M:4/4
K:Bb
 B | F<B,TF>D D>C C<D | F<B,TF>D F<dc<d | B<GTF>D D>C C<D | F<B,TF>E [B,D]2 D :| f | 
 d>Bf>B d>c c<f | d>Bf>B g>Bf>B | d<bf<g d<fc<d | B<GTF>E [B,D]2 DB | d>Bf>B dccf | d>Bf>B g>Bf>B | 
 d<bf<g d<fc<d | G<BF<B [B,D]2 DB |]  