I was asked for a bit of clarification on my last Celtic Knot Tutorial. The question was about the 4 dotted diamonds where you would insert 2 parallel lines verses the 3 dotted diamond which are left alone. I did this small, all on one page, knot to hopefully help illustrate this a bit better. The box on the top left only has the divider lines and border lines.
The second and third boxes on the top line (pictured above) have the dot that is added to each square box. I’ve numbered a few of the dots and traced around one 4 dotted diamond (add 2 parallel lines) and one 3 dotted diamond (always next to a border or divider line). The two parallel lines are added every single instance where there is a 4 dotted diamond. This will basically be the whole knot with a few exceptions along the border and divider lines.
The boxes on the bottom row show the lines being connected to complete the knot and all the dead space around the knot is filled in. I did this knot all in pencil and have squared off all my turns so you can really see how each dead space around the knot are little squares.