Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:6/8
K:G
['D DGG']  
X:1
L:1/8
M:6/8
K:G
 D | DGG GFG | A2 F D2 D | DFA ABc | BdB G2 d | Bcd dcB | e2 c A2 A | ABc cBA | BdB G2 D | 
 DGG FAA | BGG c2 A | Bcd cBA | G3 G2 ||  