Design a musical work that abides by the outlined structure and integrates the assigned theme.
X:1
L:1/8
M:2/2
K:Bb
['fgfe dedc B2 b2 b3 a g3', 'D2 F2 E2 G2 C2 A2'  
X:1
L:1/8
M:2/2
K:Bb
 fgfe dedc | B2 b2 b3 a | g3 b fdcB | cBcd F4 | fgfe dedc | B2 b2 b3 a | g3 b fdcB | cBcd B4 :: 
 D2 F2 E2 G2 | C2 A2 BdBF | D2 F2 E2 G2 | C2 A2 B4 | B,DFD B,EGE | CEAc BdBF | B,DFD B,EGE | 
 CEAc B4 :|  