Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/8
M:4/4
K:D
['AG FD FG A2 A2 dfed dcBA', 'efge =c2 c2 efge a2 fa g2'  
X:1
L:1/8
M:4/4
K:D
 AG |"D" FD FG A2 A2 | dfed dcBA |"G" B2 GB"D" A2 FA |"A7" G2 E2 E2 AG |"D" FD FG A2 A2 | 
 dfed dcBA | d2 cd efge | f2 d2 d2 :| fg | a2 fa g2 eg | f2 df ecAB | =c2 c2 efge | =c2 c2 efge | 
 a2 fa g2 eg | f2 df ecAc | d2 cd efge | f2 d2 d2 :|  