Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:1/4=100
M:2/4
K:Cmin
['', 'GG GG FF ED']  
X:1
L:1/8
Q:1/4=100
M:2/4
K:Cmin
 CD |: EC D_B, | CC DE | FD EF | G2 G2- | G2 GG | GG FF | ED GG | GG FF | ED FE | DC _B,C | 
 D2 C2- |1 C2 CD :|  