cubic
// create a 3rd order infinite polynomial surface
cubic {
<
// x^3, x^2y, x^2z, x^2,
1, 0, 0, 0,
// xy^2, xyz, xy, xz^2,
0, 1, 0, 0,
// xz, x, y^3, y^2z,
0, 0, 1, 0,
// y^2, yz^2, yz, y,
0, 0, 0, 1,
// z^3, z^2, z, C
0, 0, 0, 1
>
// sturm // optional, slower but reduces speckles
}