K525 :
-2*a^4*c^2*x^2*y + a^2*b^2*c^2*x^2*y + b^4*c^2*x^2*y +   2*a^2*c^4*x^2*y - b^2*c^4*x^2*y - a^4*c^2*x*y^2 - a^2*b^2*c^2*x*y^2 +   2*b^4*c^2*x*y^2 + a^2*c^4*x*y^2 - 2*b^2*c^4*x*y^2 +   2*a^4*b^2*x^2*z - 2*a^2*b^4*x^2*z - a^2*b^2*c^2*x^2*z +   b^4*c^2*x^2*z - b^2*c^4*x^2*z + 4*a^4*b^2*x*y*z - 4*a^2*b^4*x*y*z -   4*a^4*c^2*x*y*z + 4*b^4*c^2*x*y*z + 4*a^2*c^4*x*y*z - 4*b^2*c^4*x*y*z +   2*a^4*b^2*y^2*z - 2*a^2*b^4*y^2*z - a^4*c^2*y^2*z +   a^2*b^2*c^2*y^2*z + a^2*c^4*y^2*z + a^4*b^2*x*z^2 - a^2*b^4*x*z^2 +   a^2*b^2*c^2*x*z^2 + 2*b^4*c^2*x*z^2 - 2*b^2*c^4*x*z^2 + a^4*b^2*y*z^2 -   a^2*b^4*y*z^2 - 2*a^4*c^2*y*z^2 - a^2*b^2*c^2*y*z^2 + 2*a^2*c^4*y*z^2 = 0