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:D
['ded f2 d g2 e a2', 'aba a2 f f2 f g2 e']  
X:1
L:1/8
Q:1/8=180
M:6/8
K:D
 ded | f2 d g2 e | a2 f ded | e2 g B2 d | c2 A ded | f2 d g2 e | a2 f2 ded | 
 e2"^crot in MS" g ABd |"^crot" d3 :: aba | a2 f f2 f | g2 e e2 e | f2 d dcd | ecA A2 A | dcd ede | 
 fef gfg | aba agf | f2"^D.C." e :|  