Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:3/8=100
M:6/8
K:Gmin
['g^fg dgf g3 d2 e dcB ABc', 'G3 (Bd)f- fdB cAF cAF dcB ABc', 'dg^f gab', 'g3 fed efg cde ABc FAc dBG']  
X:1
L:1/8
Q:3/8=100
M:6/8
K:Gmin
|: g^fg dgf | g3 d2 e | dcB ABc | BAB G3 :: (Bd)f- fdB | cAF cAF | dcB ABc | BAB G3 :: dg^f gab | 
 ag^f gdB | dg^f gab | ag^f g3 :: fed efg | cde ABc | FAc dBG | cA^F G3 :|  