Random Gaussian cubic surface Seed: 28 (Gaussian coefficient and line-tracking seed)
Cubic: f(x,y,z) = -0.293 x*z^2 +0.0319 y*z^2 -0.056 z^2 -0.127 x^2*z +0.0707 x*y*z +0.225 x*z -0.00261 y^2*z -0.286 y*z +0.0993 z -0.112 x^3 +0.242 x^2*y -0.0815 x^2 +0.171 x*y^2 -0.282 x*y +0.415 x -0.195 y^3 -0.139 y^2 +0.0857 y +0.568 1
Affine cubic: f(x,y,z) = -0.293 x*z^2 +0.0319 y*z^2 -0.056 z^2 -0.127 x^2*z +0.0707 x*y*z +0.225 x*z -0.00261 y^2*z -0.286 y*z +0.0993 z -0.112 x^3 +0.242 x^2*y -0.0815 x^2 +0.171 x*y^2 -0.282 x*y +0.415 x -0.195 y^3 -0.139 y^2 +0.0857 y +0.568 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].