Random Gaussian cubic surface Seed: 209 (Gaussian coefficient and line-tracking seed)
Cubic: f(x,y,z) = -0.0678 x*z^2 -0.0764 y*z^2 -0.32 z^2 -0.0315 x^2*z -0.0207 x*y*z -0.49 x*z -0.0144 y^2*z -0.27 y*z +0.125 z -0.185 x^3 -0.359 x^2*y +0.247 x^2 +0.257 x*y^2 +0.158 x*y +0.0649 x -0.245 y^3 +0.115 y^2 -0.39 y +0.108 1
Affine cubic: f(x,y,z) = -0.0678 x*z^2 -0.0764 y*z^2 -0.32 z^2 -0.0315 x^2*z -0.0207 x*y*z -0.49 x*z -0.0144 y^2*z -0.27 y*z +0.125 z -0.185 x^3 -0.359 x^2*y +0.247 x^2 +0.257 x*y^2 +0.158 x*y +0.0649 x -0.245 y^3 +0.115 y^2 -0.39 y +0.108 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].