The white yarn is just drawing a border so I know where to put the anchoring stitches. At the bottom end, opposite the hooks, the wrap is anchored with stitches, meaning it goes into and out of the cloth I'm patching once before turning back for the next row. And at both sides at the end of each row the weft is anchored with a stitch too.
Thanks!






I got mine from Alexonver.
I haven't found a really authoritative history, but this site among others recounts: