It is closely related to the granny knot, which is also a connected sum of two trefoils.

Each of the two knots is cut, and then the loose ends are joined together pairwise.

The resulting connected sum is the square knot.

It is important that the original trefoil knots be mirror images of one another.

The square knot is amphichiral, meaning that it is indistinguishable from its own mirror image.