Craft a musical piece in accordance with the designated structure and theme.
X:1
L:1/8
M:4/4
K:D
['fd ec', '(3GFD A2 B2 A2'  
X:1
L:1/8
M:4/4
K:D
 g | fd ec d3 (A/B/4c/4) | d2 A2 GF DD | g2 fd ec d2 | (A/B/=c) G=F E=C C :| (3GFD A2 B2 A2 | 
 (3GFD AG FD D2 | (3GFD A2 B2 A2 | (B=c) G=F EC C2 | (3GFD A2 B2 A2 | (3GFD AG FD D2 | 
 (3GFD A2 B2 A2 | (B=c) G=F EC C2 ||  