Develop a musical piece employing the provided motif and an alphabet-based structure.
X:1
L:1/8
Q:1/2=100
M:4/4
K:D
['afef de B2 Adef ba f2 abfa', '[df]2 BdAd Bd A2 Acef (ba) .f2']  
X:1
L:1/8
Q:1/2=100
M:4/4
K:D
 afef de B2 | Adef ba f2 | abfa efdB | (AB)(de) ([fb] [da]) [df]2 :: BdAd Bd A2 | Acef (ba) .f2 | 
 abfa efdB | ABde fd d2 :|  