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.

The net of a triangular prism will be made of three rectangles ... The net of a dodecahedron (a platonic solid with twelve pentagonal faces) is made up of 12 regular pentagons.