The answer depends on how the pyramids are stacked.
Eight.
Pyramids can have differing amount of edges depending on the shape of the base. They can have for example a triangular base, a square base like the typical pyramids in Egypt, a pentagonal base etc.
A 2D square has 4 edges.
An octagonal pyramid has 9 faces, 9 vertices, 16 edges.
The answer depends on how the pyramids are stacked.
There are eight edges in a square based pyramid. There are also five faces and five vertices in square based pyramids.
There are lots of different types of pyramids but a square based pyramid has 5 faces, 5 corners and 8 edges
Eight.
Pyramids can have differing amount of edges depending on the shape of the base. They can have for example a triangular base, a square base like the typical pyramids in Egypt, a pentagonal base etc.
8
That solid is called a hexahedron. Many shapes meet the definition, including cubes, parallelepipeds, rhombohedrons, pentagonal pyramids, and truncated square pyramids.
5 faces 8 edges 5 vertices
7 faces 12 edges 7 vertices
Pentagonal pyramids have six faces, ten edges, and six vertices. One of the faces is a pentagonal base, the rest are triangular.
The square has 4 edges , 4 sides and 4 vertices.
A 2D square has 4 edges.