Craft a musical piece in accordance with the designated structure and theme.
X:1
L:1/8
M:6/8
K:D
['AFA fed', 'afd gab a2'  
X:1
L:1/8
M:6/8
K:D
|: AFA fed | BGB g2 B | AFA fed | BcB B2 B | AFA fed | BGB g2 g | faf gec | ded d3 :: a2 a afd | 
 gab a2 f | fga agf | gfg efg | aba afd | gab a2 g | faf gec | ded d3 :|  