Random Gaussian cubic surface Seed: 203 (Gaussian coefficient and line-tracking seed)
Cubic: f(x,y,z) = -0.0969 x*z^2 -0.0641 y*z^2 +0.173 z^2 +0.3 x^2*z -0.172 x*y*z +0.413 x*z +0.168 y^2*z -0.153 y*z -0.158 z -0.0183 x^3 -0.101 x^2*y -0.277 x^2 -0.375 x*y^2 +0.132 x*y -0.189 x +0.286 y^3 +0.389 y^2 -0.0896 y +0.26 1
Affine cubic: f(x,y,z) = -0.0969 x*z^2 -0.0641 y*z^2 +0.173 z^2 +0.3 x^2*z -0.172 x*y*z +0.413 x*z +0.168 y^2*z -0.153 y*z -0.158 z -0.0183 x^3 -0.101 x^2*y -0.277 x^2 -0.375 x*y^2 +0.132 x*y -0.189 x +0.286 y^3 +0.389 y^2 -0.0896 y +0.26 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].