Page 11 - Patrick Moreau-Marine "Knots How to Tie 40 Essential Knots"

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• perpendicular to the center, which applies to direct knots, the ones of most
interest to us. The working end is led under part 2 and over part 1.

And thus we have the alternating over-under principle.

the half knot, or simple knot
This is the simplest, most straightforward knot and the one that everyone knows.