Construct a musical composition utilizing the provided motif and conforming to the specified structure.
X:1
L:1/16
M:2/4
K:Bb
['BGFG B4', 'G2G2 G4 BGFG B4 e2de f2>d2 B2cB'  
X:1
L:1/16
M:2/4
K:Bb
 BGFG B4 | cccB d4 | B2cB G2F>G | B2B2 B4 | BGFG B4 | e2de f2>d2 | B2cB G2FG | B2B2 B4 || 
 d2de f2f2 | f2ed e4 | e2d2c2B2 | G2G2 G4 | BGFG B4 | e2de f2>d2 | B2cB G2FG | B2B2 B4 | 
 d2de f2f2 | _a2g2 f2>e2 | d2e2 d2cB | G2G2 G4 | BGFG B4 | e2de f2>d2 | B2cB G2FG | B2B2 B4 ||  