Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:4/4
K:G
['EAAF GFED (3EFG AB cAFA', 'fedf eBBB efge fdef g2 (3def ga']  
X:1
L:1/8
M:4/4
K:G
|: EAAF GFED | (3EFG AB cAFA | GBdg egdB | GBAF GFED | EAAF GFED | (3EFG AB cAFA | G3 B A2 BA |1 
 GEDE GFED :|2 GEDE GABd |: g3 e fddd | efge fedf | eBBB efge | fdef g2 (3def | ga (3bag eage | 
 dedc BcdB | GBdB c2 BA |1 GEDE GABd :|2 GEDE GABG ||  