Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/8
Q:1/8=120
M:6/8
K:D
['c2 d', 'c d2'  
X:1
L:1/8
Q:1/8=120
M:6/8
K:D
 B/c/ | dcd e2 c | d2 B A2 F | DCD E2 C | D2 E F2 G |1 A2 d c2 d | B2 G E2 D | C2 D E2 F | 
 E3 A2 :|2 A2 d c2 d | B2 G E2 C | E2 D D2 D | D3 D2 || A/^G/ |"^9" A2 B c2 d | e2 d e2 g | 
 f2 d e2 c | d2 c d2 e |"^13" f2 d e2 c | d2 B A2 F | F2 E E2 E | E3- E2 B/c/ |"^17" dcd e2 c | 
 d2 B A2 F | DCD E2 C | D2 E F2 G |"^21" A2 d c2 d | B2 G E2 C | E2 D D2 D | D3- D3 |]  