Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:2/2
K:D
['afdf afdf', '(AB d)e-e(d BA)dB A2 F2']  
X:1
L:1/8
M:2/2
K:D
 fg | afdf afdf | afaf bfbf | afdf afdf | gfef e2 fg | afdf afdf | afaf bfbf | a2 ba fedf | 
 e2 d2 d2 :: (AB | d)e-e(d BA)dB | A2 F2 [FA]3 (A | B)ABc dcde | fede f2 (AB | d)e-e(d BA)dB | 
 A2 F2 [FA]2 d(f | a2) ba fed(f | e2) d2 d2 :|  