The Falcat curve, followed until it meets itself. A knot is the oldest way to say that two things are held together, and it needs no explaining to anyone who has ever tied one.
The Falcat ring is a knot in rhodium plated silver and gold vermeil, with both metals running through the same continuous form, in sizes 52 and 55.
Wear it against the Hera ring, where two golds do the same job in a straight line.