1) For the sake of this example I’m starting out with a square folded in half
2) Fold a section of the paper to the side like in the Pleat.
3) Fold the paper back so you have a Pleat.
4) Open the paper up and you can see the creases you made.
5) Fold the paper back along the vertical creases to make another Pleat.
6) The finished Crimp.
From the side you can see that it’s kind of like two Pleats.