Triangùli in speculo (Andrea Russo), Diamond Corrugation (Ilan Garibi)

Another view of this corrugation. It was considerable easier to collapse the pattern with this side up.

 

I found 2 methods to fold this corrugation: The diagonal creases can be added with the help of a square grid, the resulting triangles are isosceles, as shown in the picture. Using a triangular grid, it is possible to create an equilateral version. This is the method Andrea Russo used.

Done