Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:4/4
K:D
['aaaf dfaf bfgg gfgb afdf Adfa', 'ffdc Bggg gggB']  
X:1
L:1/8
M:4/4
K:D
|: aaaf dfaf | bfgg gfgb | afdf Adfa | gecb afdf | aaaf dfaf | bfgg gfgb | afdf Adfa |1 
 gece defg :|2 gece d2 |: dB | Afff ffdc | Bggg gggB | Afff Adfa | gecb afdf | Afff ffdc | 
 Bggg gggB | afdf Adfa |1 gece d2 :|2 gece defg ||  