Square knot (mathematics)

Square knot
Three-dimensional view
Common nameReef knot
Crossing no.6
Stick no.8
A–B notation
Other
alternating, composite, pretzel, slice, amphichiral, tricolorable
The square knot, drawn as a ribbon knot
Square knot = trefoil + trefoil reflection. Sticks depicted.

In knot theory, the square knot is a composite knot obtained by taking the connected sum of a trefoil knot with its reflection. It is closely related to the granny knot, which is also a connected sum of two trefoils. Because the trefoil knot is the simplest nontrivial knot, the square knot and the granny knot are the simplest of all composite knots.

The square knot is the mathematical version of the common reef knot.