Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/8
M:4/4
K:G
['', 'g B<GG>A B>AB<g B<GG>A Bg A2 B<GG>A', 'g>BA<c Bd-de/f/'  
X:1
L:1/8
M:4/4
K:G
 g |: B<GG>A B>AB<g | B<GG>A Bg A2 | B<GG>A B>AB<d | e<gd<g BgAc :| Bd-de/f/ g>de>c | 
 Bd-d e/f/ g>BA<c | Bd-de/f/ g<de>d | c<gB<g a>cA<c | Bd-de/f/ g>de>d | Bd-de/f/ g>BA<c | 
 Bd-de/f/ (3gag (3ege | d<gc<g B<gA<g |]  