How a cylinder and a cube are alike?

Answer 1

Both have walls parallel to one main axis, and both have the characteristic of volume, being that they are three dimensional objects.

JCS

Answer 2

A cube, as described in computer graphics is actually topological and notionaly a sphere. This can be evidenced by the 3 spoked poles at the corners of the object. A Cubic volume is easiest to calculate using this method but the technologies we currently use to display cubes are not robust enough to properly handle the idea that a cube is not a si sided object, but more correctly is an object with a planer top face, a planar bottom face and a side described by 4 planar faces. It is a prism. More specifically, it is a cylindrical prism with a rotational order of 4 and 3 planes of volumetric symmetry. The UV sphere used in computer graphics is actually much closer to the true topology of a cube than the cube is! Because the subdivision surface algorithms employed (namely variants of catmul-clarke) do not work well with triangles, a better representation of a cube is tricky ( but certainly possible!) to create. The three spoked poles must continue to exist but can be negated within the mesh by pushing them away from the corners. While they remain at the corners or any area of deformation, the object will have elements which are spherical in nature. When such an object is created, control over curvature and flow is significantly better than with the usual pole based topology. So a cube and a cylinder are essentially very closely related.