Compound of cube and octahedron
Compound of cube ad octahedron by Francesco Mancini is licensed under a Creative Commons Attribuzione - Non commerciale - Condividi allo stesso modo 3.0 Unported License.Permissions beyond the scope of this license may be available at www.flickr.com/mancinerie.
NOTE: Each vertex of the octahedron is made by four units. Making two short pinches at step #1 can avoid the line in the middle of the final unit.
Thanks to Meenakshi Mukerji for linking this diagram to her webpage