Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/8
Q:1/2=90
M:4/4
K:F
['f2 cB', 'fg agaf gfge fefd'  
X:1
L:1/8
Q:1/2=90
M:4/4
K:F
 cB | Acfe f2 cB | Acfg f2 cB | Acfa gfed | cfag fedc | Acfe f2 cB | Acfg f2 c2 | defd efge | 
 f2 a2 f2 :: fg | agaf gfge | fefd dcBA | BcdB ABcA | B2 G2 G2 fg | agaf gfge | fefd c2 c2 | 
 defd efge | f2 a2 f2 :|  