To better illustrate the midpoint I redid this knot with one of my fused cords. These cords that I often use to tie example knots are actually shoelaces, sold locally as “oval shoelaces”. They look like president’s cord with the edge parts in a contrasting colour. I would love to find some real president’s cord in these designs as (a) shoelaces are a very expensive way to get string and (b) shoelaces are meant for dragging through the muck and aren’t exactly woven in a very refined way, so (c) real president’s cord takes the curves better and would probably have made a fine double coin example.