Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:4/4
K:A
['EAAG AcBA GABc d2 ef gfge', 'ef gfge']  
X:1
L:1/8
M:4/4
K:A
|: AG | EAAG AcBA | GABc d2 ef | gfge dcBd | cABA GEED | EAAG AcBA | GABc d2 ef | gfge edBG | 
 A2 AA A2 :: ef | gfge agae | gfge dcBd | c2 cB A2 GA | BcBA GEED | EAAG AcBA | GABc d2 ef | 
 gfge edBG | A2 AA A2 :|  