K1007 :

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