There are now two tutorials on this website for some of the techniques used to make this! They are called "Triangle end with no ties for normals" and "Triangle start with no loop or ties for normals"
@ Izzy_Raver There's a tutorial on here called "How to knot an advanced shaped normal pattern" that explains how to do some of it. Hopefully that helps because I don't know how to explain this stuff well in words. I'm going to try to work on a photo tutorial for some of this stuff but I don't know how long that will take me.
@jukey On each side, I made the border knots with just one string. So only the middle triangle end is a real triangle end. Once a string was no longer needed in the pattern, I secured it by tying the border string over it, and then I just left it out of the knot. After I was done, I glued all those ends to the back. That's why the border never gets super thick. For the final strings of the triangle end in the middle, I tied the two white border strings together, and then also glued those to the back.
and feel free to keep asking more questions if this doesn't fully make sense, I had to do a lot of weird little things to make this work
@jukey unfortunately I don't have a specific measurement, but I think they were maybe 1m long? If you're trying to do it in a similar way to me, the important thing is to make sure the string you're using to do the border is extra long.