An excellent general purpose knot for tying two pieces of string or twine together, the square knot is
possibly the most commonly used knot for the job, and is easy to learn.  However, it cannot be overly
stressed that the Square knot is not a long term or secure knot, and it should only be used to finish parcels
or bindings. In other cases, use a more secure method of bending two ropes together, such as a
Sheetbend, a Double Sheetbend, or a Fisherman's Knot.  Unfortunately, the Square knot can easily change into a slipping Lark's Head (see Lark's Head Knot), so it should never be used where life or limb are at risk.

     Holding one end of each rope in each hand, pass the left rope over the right, and tuck under. Then pass
the same rope, now in the right hand, over the left rope, and tuck under.  It is common to chant "Left over
Right and Under, Right over Left and Under" when tying the knot. (This can also be performed as "Right
over Left and Under, Left over Right and Under".)The Square knot can easliy be undone by gripping one loose end, and pulling it back over the knot, in the opposite direction, thus straightening the rope which is pulled. The other rope forms a Lark's Head knot, and slips off the tugged rope.

     This knot was also known as a "Reef Knot" getting its name from its use on sailing ship sails were
"reefed" - rolled up and tied to the cross spar with a reef knot. To release the sail, the sailors would
climb the rigging, and work their way along the cross spar, pulling the top end of the reef knot down.
They only had to use one hand, holding on with the other. The weight of the sail would cause the reef knot
to slip, and the sail would be released.

Tip. If you want to tie two ropes together of similar thickness then never use a Square knot. Only use it
with string and twine when tying parcels, whippings and bindings.

Tip. Never use this knot to join ropes of two different thicknesses.