Create a composition by utilizing the given alphabet-based musical pattern and the provided melodic theme.
X:1
L:1/4
Q:1/4=120
M:4/4
K:G
['B2 B', 'B4 d2 c c B3/2 A/ B', 'B A']  
X:1
L:1/4
Q:1/4=120
M:4/4
K:G
 B2 B B | B2 B d | c B A A | B4 :: d2 c c | B3/2 A/ B B | A G F F | E4 :: B2 G A | F3 B | A B G A | 
 F3 B | A G F F | E3 B | A G F F | E4 :|  