Random Gaussian cubic surface Seed: 340 (Gaussian coefficient and line-tracking seed)
Cubic: f(x,y,z) = 0.195 x*z^2 +0.355 y*z^2 -0.0674 z^2 +0.103 x^2*z -0.204 x*y*z -0.206 x*z -0.309 y^2*z +0.12 y*z +0.279 z -0.338 x^3 +0.225 x^2*y -0.149 x^2 +0.2 x*y^2 -0.091 x*y -0.136 x +0.316 y^3 -0.366 y^2 -0.194 y -0.154 1
Affine cubic: f(x,y,z) = 0.195 x*z^2 +0.355 y*z^2 -0.0674 z^2 +0.103 x^2*z -0.204 x*y*z -0.206 x*z -0.309 y^2*z +0.12 y*z +0.279 z -0.338 x^3 +0.225 x^2*y -0.149 x^2 +0.2 x*y^2 -0.091 x*y -0.136 x +0.316 y^3 -0.366 y^2 -0.194 y -0.154 1
Shadow: the quartic B(x,y)^2 - 4 A(x,y) C(x,y) = 0 is drawn on the z=-4 xy-plane in the same 3D scene. The translucent ruled curtain rises upward from the shadow to the ramification curve where the lifted point has z >= -2 and lies above the displayed projection plane. The 3 real projected lines on the xy-plane are bitangents found from the projective lines on the cubic surface. Same-color transparent line projection cones are included but hidden by default; use the page toggle to show them.
Viewing box: axis ranges are [-4, 4].