Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:4/4
K:Emin
['B2 AB GEEE', 'DEGE A z (A A)GAB']  
X:1
L:1/8
M:4/4
K:Emin
 B2 AB GEEE | DEGE AGGG | B2 AB GEEE | e2 dB AAGA | B2 AB GEEE | DEGE AGGG | deee edBG | 
 A2 BG AGED :| DEGE A z (A | A)GAB AGEG | DEGA G2 GA | BedB AGEG | DEGE A z (A | A)GAB AGED | 
 deee edBG |1 A2 BG AGEG :|2 AdBG A4 ||  