Tube

A tube is a two-dimensional surface constructed by creating a prism with a hollow circle as the base. It can also be considered as a two-dimensional version of the torusconstructed by stretching a line segment in a ring.

Another way to construct it topologically is to take a sphere and then remove two disjoint open discs.

A tube can also be embedded in a two dimensional plane. This less symmetric embedding is called an annulus.

Hypervolumes

 * edge length =
 * surface area =

Subafects

 * 2 circles (1D)
 * 1 tube (2D)