6 Elliptic hyperboloid of one sheet with removable octant

An elliptic hyperboloid is a solid or surface, some of whose plane sections are hyperbolas, while others are ellipses. If one of the elliptical cross-sections goes around the conjugate axis of one of the hyperbolic cross-sections, the hyperboloid has one sheet. The cross-sections in the coordinate planes may be seen by removing the octant.