If a pyramid's base has 'n' sides, then it has 'n + 1' faces, 'n + 1' vertices, and '2n' edges. For example, a pyramid with a square base will have n = 4 sides, 5 faces, 5 vertices, and 8 edges. Another interesting property is its self-dual nature. Any geometrical object may have a dual, which is another object that gets embedded inside it, in such a way, that the surfaces of the object touch the vertices of its dual. The dual of a polyhedron, like any n-sided pyramid, is the same object. That is, a dual of a pyramid is the same object. Verify it.