Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:2/4
K:E
['ed e2']  
X:1
L:1/8
M:2/4
K:E
 B2 =gf | ed e2 | BA(3B=c=d | B2 =G z | B2 gf | ed e2 | BA(3AB=c | B2 E z |]  