the objects end, the knot becomes slipped and therefore easier to untie: It also makes it possible to stretch either side rope tight by pulling at the slip loops. Variations Double constrictor knot If a stronger and even more secure knot is required an extra riding turn can be added to the basic knot to form a double constrictor knot. It is particularly useful when tying the knot with very slippery twine, especially when waxed. Adding more than one extra riding turn does not add to its security and makes the knot more difficult to tighten evenly. Make a turn around the object and bring the working end back over the standing part. Make a second turn following the same path as the first Pass the working end over the standing part, then thread it back under the standing part and both riding turns, forming an overhand knot under two riding turns. Be sure the ends emerge between the turns as shown. The double constrictor may require more careful dressing to distribute the tension throughout the knot. After working up fairly tight, pull firmly on the ends to finish. Slipped constrictor knot This variation is useful if it is known beforehand that the constrictor will need to be released. Depending on the knotting material and how tightly it is cinched, the slipped form can still be very difficult to release. Make a turn around the object and bring the working end back over the standing part. Continue around behind the object, and then again over the standing part back to the side of the first turn. Pass a bight of the working end under the point where the first riding pass and the standing part cross to form a slip loop. Be sure the slip loop bight and both ends emerge from in between the two turns as shown. To release, tug on the working end so that the bight passes back through the knot. The slipped constrictor can also be tied in the bight and slipped over the object to constrict. Despite its advertised advantage (quick release), the slipped constrictor knot can also be hard to release when worked extremely tight in certain rope materials. Cross constrictor knot This variation is similar to the double constrictor knot but has the two riding turns crossing each other rather than riding along. It is unclear whether it is more secure than