Craft a composition that integrates the assigned alphabet-related musical pattern and the provided melodic theme.
X:1
L:1/8
M:9/8
K:G
['B A2 G', 'B3 B2']  
X:1
L:1/8
M:9/8
K:G
 G2 B A2 G E3 | B2 d d2 B A2 G | G2 B A2 G E3 | def g2 B A2 G :: B3 B2 G B2 d | c2 B A2 G F2 A | 
 B3 B2 A B2 G | def g2 B A2 G :|  