Random Gaussian cubic surface Seed: 350 (Gaussian coefficient and line-tracking seed)
Cubic: f(x,y,z) = -0.0486 x*z^2 +0.284 y*z^2 -0.0561 z^2 -0.0769 x^2*z +0.349 x*y*z +0.237 x*z +0.112 y^2*z +0.0232 y*z -0.356 z -0.181 x^3 -0.0446 x^2*y -0.199 x^2 +0.18 x*y^2 -0.238 x*y -0.128 x -0.32 y^3 +0.486 y^2 +0.264 y -0.0212 1
Affine cubic: f(x,y,z) = -0.0486 x*z^2 +0.284 y*z^2 -0.0561 z^2 -0.0769 x^2*z +0.349 x*y*z +0.237 x*z +0.112 y^2*z +0.0232 y*z -0.356 z -0.181 x^3 -0.0446 x^2*y -0.199 x^2 +0.18 x*y^2 -0.238 x*y -0.128 x -0.32 y^3 +0.486 y^2 +0.264 y -0.0212 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 7 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].