Craft a composition that integrates the assigned alphabet-related musical pattern and the provided melodic theme.
X:1
L:1/8
M:4/4
K:G
['', 'BGcA defg', 'dGBd cAdc BGcB A3 G FAdf geag']  
X:1
L:1/8
M:4/4
K:G
 dc |: BGcA defg | GGBG AFDc | BGcA defg |1 dBcA G3 c :|2 dBcA G3 d || g4 fadg | e3 g dGBd | 
 cAdc BGcB | A3 G FAdf | geag fadg | e3 g dgBd | cAdc Bd g2 | dBcA G3 c ||  