Construct a melodic piece using the designated alphabetic pattern and the provided musical theme.
X:1
L:1/8
Q:1/2=90
M:4/4
K:G
['G2 BG', 'gfed Bd d2']  
X:1
L:1/8
Q:1/2=90
M:4/4
K:G
 G2 BG d2 BG | G2 BG FA A2 | G2 BG d2 BG | BABG EG G2 :: gfed Bd d2 | gfed fa a2 | gfed Bd d2 | 
 BABG EG G2 :|  