K231 :-a^4*c^2*x^2*y - 2*a^2*b^2*c^2*x^2*y + 3*b^4*c^2*x^2*y + 2*a^2*c^4*x^2*y - 2*b^2*c^4*x^2*y - c^6*x^2*y + 3*a^4*c^2*x*y^2 - 2*a^2*b^2*c^2*x*y^2 - b^4*c^2*x*y^2 - 2*a^2*c^4*x*y^2 + 2*b^2*c^4*x*y^2 - c^6*x*y^2 - a^4*b^2*x^2*z + 2*a^2*b^4*x^2*z - b^6*x^2*z - 2*a^2*b^2*c^2*x^2*z - 2*b^4*c^2*x^2*z + 3*b^2*c^4*x^2*z + 2*a^6*x*y*z - 2*a^4*b^2*x*y*z - 2*a^2*b^4*x*y*z + 2*b^6*x*y*z - 2*a^4*c^2*x*y*z + 12*a^2*b^2*c^2*x*y*z - 2*b^4*c^2*x*y*z - 2*a^2*c^4*x*y*z - 2*b^2*c^4*x*y*z + 2*c^6*x*y*z - a^6*y^2*z + 2*a^4*b^2*y^2*z - a^2*b^4*y^2*z - 2*a^4*c^2*y^2*z - 2*a^2*b^2*c^2*y^2*z + 3*a^2*c^4*y^2*z + 3*a^4*b^2*x*z^2 - 2*a^2*b^4*x*z^2 - b^6*x*z^2 - 2*a^2*b^2*c^2*x*z^2 + 2*b^4*c^2*x*z^2 - b^2*c^4*x*z^2 - a^6*y*z^2 - 2*a^4*b^2*y*z^2 + 3*a^2*b^4*y*z^2 + 2*a^4*c^2*y*z^2 - 2*a^2*b^2*c^2*y*z^2 - a^2*c^4*y*z^2 = 0