Why is a cross section of a polyhedron not always match the base of that polyhedron?

A cross section of a polyhedron is formed by slicing the polyhedron with a plane, which can intersect the faces, edges, and vertices in various ways. Depending on the angle and position of the slicing plane, the resulting cross section can produce shapes that differ significantly from the base of the polyhedron. For example, slicing a rectangular prism diagonally can yield a triangular cross section, illustrating how the orientation of the cut affects the shape. Thus, the cross section may not necessarily match the base due to these factors.