Assemble a piece of music by merging the alphabetic representation of the predetermined musical pattern and the provided melodic theme.
X:1
L:1/8
M:2/2
K:D
['GFGA B2 gB fB e2', 'B e3']  
X:1
L:1/8
M:2/2
K:D
 BGEF GFGA | B2 gB fB e2 | BGEF GBAG | (3FED AD BDAD | EDEF GFGA | B2 gB fB e2 | d2 ce dBAF | 
 DFAF GE E2 :: B e3 B e3 | Beef edBc | d A3 f A3 | dAce dBAF | EDEF GEGA | B2 gB fB e2 | 
 d2 ce dBAF | DFAF GE E2 ||  