Bowline on a bight advocate the use of a figure eight twisted version of the Bowline on a bight. This knot can be used to provide a toe hold in the middle of a rope; to make an emergency bosun's chair; and to create an upper rope "block" to make a crude purchase by threading the rope round an anchor point and then back up through the loop. It is sometimes used in sport climbing to tie into two anchor bolts independently. This knot is convenient when a dependable loop is required but neither end of the line is available. It's also commonly used
Overhand knot There are a number of ways to tie the Overhand knot. In heraldry, the overhand knot is known as a "Stafford knot", owing to a representation of it being used first as a heraldic badge by the Earls of Stafford, and later as a general symbol of Staffordshire. As a defensive measure, hagfishes, which resemble eels, produce large volumes of thick slime when disturbed. A hagfish can remove the excess slime, which can suffocate it in a matter of minutes, by tying its own body into an overhand knot, then sliding the knot from its head down to the tail.