Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/4
Q:3/4=100
M:6/4
K:D
['(B/c/) (d c) B (A G) F', 'g f'  
X:1
L:1/4
Q:3/4=100
M:6/4
K:D
 (B/c/) | (d c) B (A G) F | (G A) F E2 D | (C D) E A,2 (B/c/) | (d c) B (A G) F | (G A) F E2 D | 
 D3- D2 || (f/e/) | d2 d (f g) a | e3/2 f/ g f d f | a3 b a g | f a2 e g2 | (d e) f (e c) A | 
 d3- d2 |]  