Sett in Stone: Building a Tartan Designer That Obeys the Thread Count
A browser-based tartan designer is mostly a list, a mirror and a modulo operation — but the details are where it earns its keep. Here's how to expand a sett into a proper 2/2 twill weave in SVG or canvas, catch the halving-and-doubling mistakes before they ship, and handle named setts with the care they deserve.