// create a 4th order infinite polynomial surface
quartic {
<
// x^4,        x^3y,       x^3z,       x^3,        x^2y^2,
   0,          0,          0,          0,          0,
// x^2yz,      x^2y,       x^2z^2,     x^2z,       x^2,
   0,          0,          0,          0,          0,
// xy^3,       xy^2z,      xy^2,       xyz^2,      xyz,
   0,          0,          0,          0,          0,
// xy,         xz^3,       xz^2,       xz,         x,
   0,          0,          0,          0,          0,
// y^4,        y^3z,       y^3,        y^2z^2,     y^2z,
   0,          0,          0,          0,          0,
// y^2,        yz^3,       yz^2,       yz,         y,
   0,          0,          0,          0,          0,
// z^4,        z^3,        z^2,        z,          C           
   0,          0,          0,          0,          0
>
  sturm // optional, slower but reduces speckles
}