1. The intersection of two faces is an edge. Refers to a strip-shaped protrusion on an object, or a part where two planes in different directions are connected. If you are in a cube and a cuboid, you have 12 sides, which have different characteristics in different geometric shapes.

2. Geometrically, a pyramid, also known as a pyramid, is a three-dimensional polyhedron, which is formed by connecting each vertex of a polygon to a point outside its plane in turn. The polygon is called the bottom of the pyramid. With the shape of the bottom, the name of the pyramid is different, depending on the polygon at the bottom. For example, a pyramid with a square base is called a square pyramid, a pyramid with a triangular base is called a triangular pyramid, and a pyramid with a pentagonal base is called a pentagonal pyramid.