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
['cAeA cAeA']  
X:1
L:1/8
M:4/4
K:Amin
"Am" A a2 g a2 ef |"G" gedB GA(3BAG |"Am" A a2 g a2 ef |"G" gedB"Am" A2 AB :|"Am" cAeA cAeA | 
"G" BcdB G4 |"Am" cAeA cAeA |"G" BA(3GAB"Am" A4 |"Am" cAeA cAeA |"G" BcdB G4 |"F" ABcd"Em" efga | 
"G" gedB"Am" A4 |]  