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:Gmin
['B G<GG>F D>FTF>B G<GG>A B>cd>g G<GG>F D>FFB', 'DGG ^f g>dgb =f>cfa g>dg>b g>af>g d>fc>f'  
X:1
L:1/8
Q:1/4=120
M:4/4
K:Gmin
 B | G<GG>F D>FTF>B | G<GG>A B>cd>g | G<GG>F D>FFB | G>AB>c dg^fg | G<GG>F D>FTFB | G<GG>A B>cdg | 
 G<GG>F DFFB | G,>A,B,>C DGG || ^f | g>dgb =f>cfa | g>dg>b g>af>g | d>fc>f A<FF>A | G<ABc d<g Tg2 | 
 gdgb fcfa | gdgb gafg | d>fc>f AFFA | G,>A,B,>C DG>G |]  