Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:1/8=180
M:6/8
K:Amin
['e dBd', 'a^ga e^f^g a^ga e2 ^f']  
X:1
L:1/8
Q:1/8=180
M:6/8
K:Amin
|: a | eAe edB | dBA A2 B | G2 e dBd | BAG G2 g | ^fed e^fg | a^ga e2 ^f | g2 e dBd | e2 A A2 :: 
 e | a^ga e^f^g | a^ga e2 ^f | g^fg de^f | g^fg e2 ^g | a^ga e^f^g | a^ga e2 ^f | g2 e dBd | 
 e2 A A2 :|  