Copy this page, and then cut out the above corrugated pyramid shapes. Because so many edges meet at the central vertex, it is difficult to make these nicely. You might think of first enlarging the shapes before cutting and folding. Cundy and Rollett advise using a strengthening pair of equilateral triangles inside each pyramid to strengthen it. The edges with unnamed outer vertex fold inwards, the other edges outwards. The short edge of each exterior triangle glues to the adjacent edge of a vertex triangle. You finish up with a corrugated pyramid standing on a pentagonal base. Finally use the figure in the main text to assemble and glue the pyramids together.