Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:3/4
K:G
['GA B2 A<B G<E DE GG G2']  
X:1
L:1/8
M:3/4
K:G
 GA | B2 A<B G<E | DE GG G2 | z G>B ddB | G B>A B A2 | z GB ddB | de dB A2 | G A<B A<B G | 
 ED EG G<G |]  