Construct a musical composition following the given alphabetical structure and incorporating the specified motif.
X:1
L:1/8
M:6/8
K:G
['g2 d dec BAG', 'dcB dcB']  
X:1
L:1/8
M:6/8
K:G
 g2 d dec BAG | e2 A ABG FED | g2 d dec BAG | g2 f ed^c d3 :: B2 c dcB dcB | e2 f gfe gfe | 
 dBc dcB dcB | c2 B AGF G3 :|  