Catenary curve. Yes, it was difficult for me to learn to make this pattern, as difficult as it sounds, or worse. But now I can do it and I love to make this pattern in many variations. Catenary is the curve that occurs when you hold a chain of pearls in both ends. It can be wide or narrow. It is the same system that is often used in the construction of bridges. Like The Great Belt Bridge. And the color is my favorite prussian blue with all its nuances.