Let us consider a tetrahedron OABC where O(0,0,0), A(1,1,1), B(1,-1,1), C(1,1,-1). The volume of tetrahedron ` \ ^G1^G2^G3^G4 \ where\ ^G1,^G2,^G3,^G4` are the centroids of the 4 faces of the tretrohedron OABC is