K985 :

a b^4 c x^2 y-a^3 c^3 x^2 y-a^4 b c x y^2+b^3 c^3 x y^2+a^3 b^3 x^2 z-a b c^4 x^2 z-a^3 b^3 y^2 z+a b c^4 y^2 z+a^4 b c x z^2-b^3 c^3 x z^2-a b^4 c y z^2+a^3 c^3 y z^2=0