Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:1/8=180
M:6/8
K:A
['aec ecA']  
X:1
L:1/8
Q:1/8=180
M:6/8
K:A
|: B | cde eAa | cAc e2 d | cde ef=g | B=GB d2 B | cde efg | agf edc | dbd cac | B=GB d2 e | 
 aec ecA | aec efg | aec ecA | B=GB d2 e | aec ecA | aec efg | aec ecA | B=GB d2 :|  