This is how the knot is tied ...

the knot will tie itself again in a few seconds

The knot should look like this when you are done

The square knot is an old sailing knot that is used to store a sail by wrapping it around a spar (the cross piece on a mast) and securing it with a square knot. Because this is called reefing the sail, another name for the square knot is the reef knot.