##### Wikipedia

**Spherinder**

In four-dimensional geometry, the **spherinder**, or **spherical cylinder** or **spherical prism**, is a geometric object, defined as the Cartesian product of a 3- ball (or solid 2- sphere), radius *r* and a line segment of radius *r*:

*D* = {(*x*, *y*, *z*, *w*)∣*x* + *y* + *z* ≤ *r*, *w* ≤ *r*}

Like the duocylinder, it is also analogous to a cylinder in 3-space, which is the Cartesian product of a disk with a line segment.

It can be seen in 3-dimensional space by stereographic projection as two concentric spheres, in a similar way that a tesseract (cubic prism) can be projected as two concentric cubes.