Design a musical work that abides by the outlined structure and integrates the assigned theme.
X:1
L:1/8
Q:1/2=60
M:4/4
K:Bb
['B BFFF FD F2 FGBc d2 c2', 'BcdB cdec'  
X:1
L:1/8
Q:1/2=60
M:4/4
K:Bb
 B | BFFF FD F2 | FGBc d2 c2 | BGGB GFGB | FGBc d2 c2 || BcdB cdec | BcdB c2 BG | BcdB cdec | 
 dfFe d2 c |]  