Develop a musical composition in line with the given structure and theme.
X:1
L:1/8
M:4/4
K:G
['BB B2']  
X:1
L:1/8
M:4/4
K:G
 z2 BB | B2 AA A2 cc | c2 BB B2 GG | G2 F2 G2 A2 | B6 BB | B2 AA A2 cc | c2 BB B2 c2 | 
 de dc B2 A2 | G4 :|  