Compose a musical piece using the designated musical pattern's alphabetic representation and the assigned melodic theme.
X:1
L:1/8
M:6/8
K:G
['g2 f g2 d e>fg f2 d', 'BGA BGA']  
X:1
L:1/8
M:6/8
K:G
 g2 f g2 d | e>fg f2 d | B>cd e2 d | cdB A2 G | g2 f g2 d | e>fg f2 d | B>cd e2 d | cBA G3 :: 
 GGA BGA | BGA BGA | GGA BGA | BGA G3 :|  