I took some clear acetate, wrapped around the glass and taped together, drew over the spiral of color to cut for a template. Since the thickness of the leather will shift the pattern a bit, I used this scrap to test it. Using a utility knife with the blade retracted most of the way so I could rest the tip of the handle on the template--makes it easier for me to trace the cut with less blade going around curves, the blade cut the stiffer grain side but didn't go all the way through. Before finishing the cuts, I did flex and fold it much as you did the paper.
However, a court in Japan has asserted that the folding method of an origami model "comprises an idea and not a creative expression, and thus is not protected under the copyright law".  Further, the court stated that "the method to folding origami is in the public domain; one cannot avoid using the same folding creases or the same arrows to show the direction in which to fold the paper". Therefore, it is legal to redraw the folding instructions of a model of another author even if the redrawn instructions share similarities to the original ones, as long as those similarities are "functional in nature". The redrawn instructions may be published (and even sold) without necessity of any permission from the original author. The Japanese decision is arguably in agreement with the . Copyright Office, which asserts that "copyright does not protect ideas, concepts, systems, or methods of doing something."