Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:4/4
K:Amin
['a2 e=f ecAc BABc', 'EcdB A2 z']  
X:1
L:1/8
M:4/4
K:Amin
|: a2 e=f ecAc | BABc BGA z | EAcA EAcA | BABc ABce | a2 e=f ecAc | BABc BGE z | EFAc dcAF |1 
 EcdB A2 z g :|2 EcdB A2 z d || eAAe fzzf | eAAe dAAd | ABcd edea | gecd efed | eAAe fzzf | 
 ^fAAf =fAAf | EFAc dcAF |1 EcdB A2 z d :|2 EcdB A2 z g ||  