The Origami Forum

Please can someone help me with David Derudas Cobra?
I have made the head but am stuck from step 15.
What is the 'X'
Is this from where u start to fold step 16?
To do step 16 do i have to open up the book folded sides?
I can do one of the pleats shown in step 17 & 18 but how to carry on? do repeat ? but if u do u end up pleating over the first crossed pleat and the paper gets too thick
if any one has photo diagrams /video tutorial that would be great

Imtiaz

It shows opening the book folds in 15. The X is a place without landmarks, and you start to fold 16 from there. You pleat over the first crossed pleat, and the second, third,... You get a scale pattern, but the paper isn't that thick. Step 16 says to precrease the entire rest of the model into diagonal 16ths,like shown.