The elongated triangular pyramid can form a tessellation of space with square pyramids and/or octahedra.

What is the difference between a pyramid and a triangular pyramid?

A pyramid is a polyhedron for which the base is a polygon and all lateral faces are triangles. ... A pyramid is typically described by the shape of its base. For instance, a triangular pyramid has a base that is a triangle, and a hexagonal pyramid has a base that is a hexagon.

What shape is two pyramids put together?

An octahedron is a shape that is formed by joining by two pyramids at its bases. Once joined the shape converts to 8 faced, 12 edges, and 6 vertices. An octahedron is most commonly known as the regular octahedron i.e. when all the faces are of the same shape and size.