Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
Q:3/8=90
M:6/8
K:Gmin
['D (GB/c/)d dBG (FA/B/)c cAF G(B/c/d) g(=e/f/g)', 'G2 A B2 B BgB BgB AGF']  
X:1
L:1/8
Q:3/8=90
M:6/8
K:Gmin
 D | (GB/c/)d dBG | (FA/B/)c cAF | G(B/c/d) g(=e/f/g) | d(B/c/d) cBA | G(B/c/d) dBG | 
 F(A/B/c) cAF | GBd gfd | cBA G2 :: A | B2 B BgB | BgB AGF | G2 g gba | gba g3 | bag fed | 
 cdB AGF | GBd gba | gdB G2 :|  