Drawing borders in Celtic art style is basically the same process we used previously to draw knot panels.
We'll start by drawing a 3 row x n column grid, like this one at the bottom.
Then, we'll draw the basic patterns already know to build the interlacing loop of the borders knot.
Here, in red, is featured the pattern upper and the pattern mirrored down.
The intertwined knots are made...
Based on the previous sketch, we will draw the entire route with a wider and coloured line.
Drawing the outlines...
... until the finish presentation.