a plane with a flexible face that can plane concave or convex surfaces.
With the viscosity solution of Eikonal equation, a method is proposed on the 3D reconstruction of convex surface based on an image. Then, the additive saddle surface and multiplicative saddle surface are defined.
The increasing Rotation number weakens curvature effect on convex surfaces, while strengthens curvature effect on concave surfaces.
The convex surface of that stone has the mark of dragon.
A convex surface, body, part, or line.
