Construct a musical composition following the given alphabetical structure and incorporating the specified motif.
X:1
L:1/8
Q:1/2=60
M:2/4
K:G
['g fedc BGGd gggg a/g/f/e/ dg fedc', 'cA A/B/c/d/ BGGB']  
X:1
L:1/8
Q:1/2=60
M:2/4
K:G
 g | fedc | BGGd | gggg | a/g/f/e/ dg | fedc | BAGB | cedF | G3 :: B | cA A/B/c/d/ | BGGB | 
 c/B/A/G/ c/B/A/G/ | dDDB | cA A/B/c/d/ | BGGB | BG B/A/G/F/ |"^cr.in ms" G3 :|  