There's a trick to getting the triangle to open and flatten and I *think* I have it now, but another round of your [wonderful!] video will help.
It appear my informational reply did not go through.The "trick" is the mountain fold obtained by pushing down on the point of the triangle as you push the mountain folds in the direction chosen.
Diagram showing this may be seen at www.orifun.weebly.com OriFUN to all,Dianne
