Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/8
Q:1/4=120
M:4/4
K:C
['c2 c2', 'cBdB G2'  
X:1
L:1/8
Q:1/4=120
M:4/4
K:C
{a} g>^fg>a g>=fe>d | c2 c2{d} cBcd | e2 e2{f} e>de.f | c2 c2 c2 ef |{a} g>^fg>a g>=fe>d | 
 c2 c2 cBcd | e2 e2 d>ef>d | c2 e2"^cr.in ms" c4 :| c>Bc>d e2 z c | cBdB G2 AB | c>Bc>d edec | 
 cBdB G2 z2 | g>fe>f g>ab>c' | g>fe>f g>ab>c' | e2 e2 d>ef>d | c2 e2 c2 ef!D.C.! |]  