Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:1/4=120
M:6/8
K:Gmin
['D G>AG B>cB (A<F)F F2 A G>AG', '=e fgf f_ed cdB ABc d>ed d2', '', 'd g>ag gab (a<f)f f2 a g=e^f', '=e fgf f_ed cdB ABc d>ed d2']  
X:1
L:1/8
Q:1/4=120
M:6/8
K:Gmin
"^With spirit""^A" | D | G>AG B>cB | (A<F)F F2 A | G>AG g>ag | (f<d)d d2"^B" || =e | fgf f_ed | 
 cdB ABc | d>ed d2 c | (B<G)G G2 |]"^C" |] d | g>ag gab | (a<f)f f2 a | g=e^f gab | afd d2"^B" || 
 =e | fgf f_ed | cdB ABc | d>ed d2 c | (B<G)G G2 |]  