Knot point constructed on the standing end (such as a loop or overhand knot) into which the working end is easily hitched, using a round turn. An example of this is the bowline. "Constricting" knots often rely on friction to cinch down tight on loose bundles; an example is the Miller's knot. Knots may belong to more than one category. Trick knots are knots that are used as part of a magic trick, a joke, or a puzzle. They are useful for these purposes because they have a deceptive appearance, being easier or more difficult to tie or untie than their
Reef knot reef knot must emerge both at the top or both at the bottom, otherwise a thief knot results. Although the reef knot is often seen used for tying two ropes together, it is not recommended for this purpose because of the potential instability of the knot, and over-use has resulted in many deaths (see Misuse as a bend). The reef knot is at least 4,000 years old. The name "reef knot" dates from at least 1794 and originates from its common use to reef sails, that is to tie part of the sail down to decrease its effective surface area