6 × 3 = 18. A hexagonal prism has 18 edges. Image caption, The vertices of a prism are at each end of the 3D shape. The number of vertices is twice the number of vertices of an end face.

This is called a hexagonal prism. Some 3D shapes, like cubes and pyramids, can be opened or unfolded along their edges to create a flat shape. The unfolded shape is called the net of the solid.