Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/8
M:6/8
K:D
['FED FGA', 'd2 f'  
X:1
L:1/8
M:6/8
K:D
|: A/G/ | FED FGA | dfd ecA | FED FGA | GEF GFE | FED FGA | d2 f ecA | f^ef g=ec | Ad[cd] d2 :: A | 
 dff f^ef | df/e/d AFD | d/e/fe d2 f | e^de gfe | d2 f f^ef | dfd AFD | Ac/B/A GEF | ED[CD] D2 :|  