Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:6/8
K:G
['', 'D GBA AGE GAG GBd ege dBG', 'edB g2 g edB BAG A2 D']  
X:1
L:1/8
M:6/8
K:G
 D |: GBA AGE | GAG GBd | ege dBG | BAG A2 D | GBA AGE | GAG GBd | ege dBG |1 AGF G2 D :|2 
 AGF G2 B |: def g3 | age edB | g2 g edB | BAG A2 D | GBA AGE | GAG GBd | ege dBG |1 AGF G2 B :|2 
 AGF G2 ||  