Page 110 - Patrick Moreau, Jean-Benoit Heron Marine Knots How to Tie 40 Essential Knots

This knot makes use of the figure-eight knot’s various qualities.
It is very useful for landing a halyard using a hoist and it allows you to
quickly create an attachment point that is easy to tie and untie even after
intense use, without using one of the ends.
There are a wide variety of knots that use the principles of the figure-
eight knot.

And this is one of the simplest.