This is a very common mistake made by people learning to tie a reef knot. The square knot is the mathematical version of the common reef knot. A square knot is another name for a reef knot. It is better to tie a reef knot in nearly all circumstances. The thief knot is much less secure than the already insecure reef knot. The name "square knot" is often used for the unslipped version of reef knot. The reef knot figures prominently in Scouting worldwide. The reef knot is of ancient origin. The arms show a red reef knot on a gray background. The reef knot or square knot represents the strength of World Scouting. The reef knot is at least 4,000 years old. It is considered inferior to the reef knot (square knot), which it superficially resembles. The common reef knot (square knot) is sometimes mistakenly tied as a bend. A reef knot, when misused as a bend, can capsize dangerously.