Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:3/8=128
M:6/8
K:Emin
['G3 g2 e dBG AGE DEG BAG', 'e^de gfg', 'g gdB']  
X:1
L:1/8
Q:3/8=128
M:6/8
K:Emin
 (3D/E/F/ | G3 g2 e | dBG AGE | DEG BAG | BAA (A2 B/A/) | G3 g2 e | dBG AGE | DEG BAG | AGF G2 :| 
 d | e^de gfg | e^de gfg | e^de gfg | fdB B2 d | e^de gfg | agf gfe | BcB AGA | BGE E2 :| 
 (3D/E/F/ | G2 g gdB | G2 g gdB | DFA cBA | BFA GFE | D2 g gdB | G2 g gdB | BcB AGA | BGE E2 :|  