Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:4/4
K:Amix
['a A<Ae>d Bd e2 d>gB>g d>gB>G A<Ae>d', 'a2 e>a']  
X:1
L:1/8
M:4/4
K:Amix
 a | A<Ae>d Bd e2 | d>gB>g d>gB>G | A<Ae>d Bdea | g<eg>B A<AA :: e | a2 e>a c>ae>f | 
 g2 d>g B>gd>e | a2 e>a c>ae>a | g<eg>B A<AA :|  