I suddenly feel like one of those old guys who have decades of expertise in some particular area, and they CANNOT answer a question about it without giving examples and counterexamples and basically explaining every ramification of every point the question touches? That is now me. And it's only going to get worse, bc in the book I'm using for reference, in about two chapters the author demonstrates a technique to create a 10 x 10 square grid by drawing an eight-pointed star inside a quartered square, and you just know I am WITH CHILD (as Stephen Maturin would say), to write a proof for it. ~~~ Also, in retrospect I would like to point out the sketch on the left isn't really a plait, imho? More like a twist, or you could make it into a chain---WAIT! NO! STOPPING NOW