So I thought I'd replace the towel on their perch in one of our windows ... fur sticks to the cushion on the perch so I'd put a towel on it (the towel is easier to wash than trying to get fur off the cushion).
I bought some Cuddly Chenille (Paradise Isle) by Loops & Threads for it. The recommended needle size is 8mm. As I was knitting it, I noticed it was knitting really thick and tight. I don't have a bigger needle so I kept going. It turned out to be more of a mat than a blanket, which I think should work out okay. Neither cat has checked it out yet (they are sleeping on our bed).
I measured the perch width-wise and it was 16 inches so that's how many stitches I put on. I did a garter stitch until I ran out of yarn.