Meanings and beliefs tied into knots.
The simpliest knot can be a sacred symbol.
From the time of the Ancient Greeks, and Egyptians, we know that knots had a lot of significance, like the Knot of Hercules, ( reef or square knot), which they believed could promote healing when tied around a bandaged injury.
In Egypt an Isis knot amulet was thought to be a powerful protective symbol in the afterlife, mentioned in the Book of the Dead, as being made from red stone, and representing a piece of knotted cloth.
Knots are mentioned in most religions, wearing tassels to remind them of their faith, to be aware of people wishing them harm through tied knots, and others have protective knots that are allowed to fall off in their own time.
Celtic Knots have no end or beginning, so they can represent the enduring spirit of nature, or an uninterupted life cycle, both for Pagans and early Celtic Christians. Here in Cornwall they are often carved on Celtic cross headstones. Leonardo Da Vinci and Albrecht Durer were both fascinated by very intricate knotwork working from one length of thread, in their drawings and woodcuts.
Every culture must have some similar knowledge of knotting.
The Incas in Peru had a language and calculator created with knots called Quipus. The more I research, the more I am amazed at how inventive people have been with twine or thread.
Going at a rate of knots
Talking about calculating with knots, on a ship they can tell you how fast you are going.
The nautical knot is named after the knots on a ship's log, which calculated the speed of the vessel. A weighted wooden drogue with a long line of cord with knots tied at known intervals is allowed to run out, through the hand and after a specified time (28 seconds), the line is stopped, and the amount of knots that have gone out is the speed you are travelling.
In the days of sailing ships, when all global commerce depended on the wind, sailors used to buy wind in the form of knots from women. These witches promised that when the first one was untied, they would get a gentle breeze, the second would bring a good wind, and the third would fetch up a gale. In 1350 Ranulph Higden, a Benedictine monk reported in his Polychronicon that women on the Isle of Man would sell wind to sailors with three knots of thread.
Witches also used numbers and knots for other spells, some numbers were preferred, like three, nine, and thirteen. Knotted into rope, spells were thought to have bound people's mouths closed, prevented them doing something or even stopped pain. Witches ladders are knot and charms woven together with whatever intention in mind along a rope.
If a knot spell was thought to be harmful to you, you should find it, to undo the knots and burn it.
I have no real interest in creating knot spells, I just like doodling with rope, with nothing more magical in mind than creating a new basket or mat!