Schematized diagram of simplest shoe-tying knot (slipped square-knot or "bow").
Made from circular arcs, horizontal lines, and lines at 45-degree angles, with a requirement that structural knot crossings be shown as close to perpendicular as possible (see also Knots-decorative-inline.svg).

Crossings at 45° or 135° (as opposed to quasi-perpendicular crossings near 90°) are not structurally significant...
Own work Converted from the below vector PostScript code
AnonMoos