Random Gaussian cubic surface Seed: 307 (Gaussian coefficient and line-tracking seed)
Cubic: f(x,y,z) = -0.0374 x*z^2 +0.137 y*z^2 +0.0666 z^2 -0.0434 x^2*z -0.187 x*y*z -0.23 x*z +0.204 y^2*z +0.22 y*z -0.468 z +0.0943 x^3 -0.25 x^2*y -0.13 x^2 +0.287 x*y^2 +0.263 x*y +0.178 x -0.148 y^3 +0.118 y^2 +0.255 y +0.451 1
Affine cubic: f(x,y,z) = -0.0374 x*z^2 +0.137 y*z^2 +0.0666 z^2 -0.0434 x^2*z -0.187 x*y*z -0.23 x*z +0.204 y^2*z +0.22 y*z -0.468 z +0.0943 x^3 -0.25 x^2*y -0.13 x^2 +0.287 x*y^2 +0.263 x*y +0.178 x -0.148 y^3 +0.118 y^2 +0.255 y +0.451 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].