Drahtmodell einer Glockenfläche

Kurzbeschreibung: The model shows the lines of curvature, i. e. the meridians and parallels of the surface of revolution. The regions of the elliptic and hyperbolical points are separated by the parallel belonging to the point of inflexion of the meridian. The parallel itself consists only of parabolic points. In the model elliptic, parabolic, and hyperbolical points are marked by yellow, white, o…