I used hemp cord to crochet over rag yarn I’d made from a bedsheet. It’s the same idea as the baskets made by crocheting around clothesline, but the cording ends up being stiffer than the base with this version.
The sides go up higher than I’d expected (I didn’t want to waste any of the materials so I just kept going until I ran out), so folding over the top makes it more sturdy and cat-friendly:
It took her a couple weeks to try sitting in it, but the slobbering (zoom in) says it’s been approved!
I spent much of last year trying to make a rug instead, using this tutorial/inspiration, but kept having to redo it when it wouldn’t lie down flat (partly a problem of using a stiff cord rather than yarn). And at some point I realized a white rug was a bad idea for my house, anyway.