Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
Q:1/4=80
M:6/8
K:Eb
['G B c2 d c2 G (B3']  
X:1
L:1/8
Q:1/4=80
M:6/8
K:Eb
 G B | c2 d c2 G | (B3 B) G F | E2 E F2 E | G3 z G B | c2 d c2 G | (B3 B) G F | E2 E F2 G | 
 (E3 E) |]  