3 strands held together. Start with 8 sc in magic loop. Increase 8 sts each round (unless it’s starting to ripple around the edges: if so, do an even round with no increases). All sts worked in the back loop (to get nice ridge throughout), rounds in continuous spiral.

Need to lay it out after each round to see what to do in the following round (whether to increase or not).

Tip: put st markers into the sts where the increases will go. Shift them around a bit before each round so you avoid points/corners at the increases. I usually moved each marker to the left by 2-3 sts after each round. As it got really big, then I moved them 4 sts over.

Magic knot for joining new yarn: https://www.youtube.com/watch?v=s7cPt_KoSU8

38” in diameter to match the same size as my now-worn rug from my Grandmother, which I’m about to part with..