Spanish bowline Spanish bowline The Spanish bowline is a double loop knot that can be used to lift a person. For a conscious person, each loop is placed around a leg and the person holds onto the standing part of the rope. This knot can serve as a makeshift Bosun's chair. For an unconscious person one loop is placed around the arm pits and the second loop is placed around the knees. This knot has an elegant symmetry and can be tied quickly when mastered. Unlike the Portuguese bowline, each loop is separately fixed, which is a nice feature. It is a
Mutation (knot theory) Mutation (knot theory) In the mathematical field of knot theory, a mutation is an operation on a knot that can produce different knots. Suppose "K" is a knot given in the form of a knot diagram. Consider a disc "D" in the projection plane of the diagram whose boundary circle intersects "K" exactly four times. We may suppose that (after planar isotopy) the disc is geometrically round and the four points of intersection on its boundary with "K" are equally spaced. The part of the knot inside the disc is a tangle. There are two reflections that switch pairs of