Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
Q:3/8=68
M:6/8
K:Eb
['B BcB efe', 'B2 B BcB edc', 'B2 B BcB efe', 'A2 G/A/ BcB AFD E3-']  
X:1
L:1/8
Q:3/8=68
M:6/8
K:Eb
 B | BcB efe | dBB B2 || B | BcB edc | B3- B2 || B | BcB efe | dBG A2 || G/A/ | BcB AFD | E3- E2 |]  