This is a Reef knot tied using two bights. Nice little trick and a very clear explanation. We would use a knot similar to this when furling the foresail on sch

This is a Reef knot tied using two bights. Nice little trick and a very clear explanation. We would use a knot similar to this when furling the foresail on schooners, as it easily untied under sail. If the author wanted a slight improvement in the explanation, mine would make the finger diagrams use a transparency for the thumb and index finger so that the reader could interpret the location of the laces behind the fingers.