cp albero di Natale di piramidi Piramide seconda

[gingerbread]

First CP I tried ( with some success at least). The tree does not seem to lock well for me though at the end. Using copy paper as suggested on Franceso Guarnieri's web site http://guarnieri-origami.blogspot.it/se ... el/modular The CP is there. MIne looks like the photos, but the bottoms come apart, despite reinforcing creases with the back of a metal spoon. I am guessing I am doing something wrong with the corners of the CP. After collapsing one of the squares into a triangle I thought I should valley fold the crease that extends a quarter of the width of the whole pattern and then fold a little triangle over it to lock it and then the rest kind of pops into place. I use paper clips to hold each quarter (side) of the tree while I do the other three sections, but even after recreasing it still seems to let go. Practice needed or am I reading the CP incorrectly? Help please. Thank you.