The discovery came about because I've ordered a copy of Sequence Knitting by Cecelia Campochiaro. I've been hearing about the book since it was published, e.g. in Tom of Holland's blog, here. It's not easy to buy it in the U.K., so I have finally ordered a copy from the U.S., and it is now making its way slowly over the Atlantic (I hope). After I ordered it, I started thinking about the kind of sequences that I think she's talking about. One idea is to choose a sequence of knit and purl stitches and repeat them over and over on every row, so every row starts at the beginning of the sequence. You get different stitch patterns depending on the number of stitches you have. So for instance, the simplest sequence would be K1, P1. If you have an even number of stitches, you get single rib, and an odd number of stitches gives moss stitch. It's fascinating that two stitch patterns which look and behave so differently should be so closely related.
Then I started thinking about the sequence K2, P2. If the number of stitches is a multiple of 4, you get double rib, and if it's a multiple of 4, plus 2, you get what's sometimes called double moss stitch. And if it's a multiple of 4, plus 1 or 3, I discovered that you get an interesting stitch pattern that's a mixture of single rib and moss stitch.
The resulting fabric is deeply corrugated and quite stretchy, but doesn't pull in like double rib.
I thought that such a simple but good-looking stitch pattern must be already known, and not a new invention. And a few days later, in the way that coincidences happen, I found a knitting pattern that uses it.
It would be nice to knit something more than a swatch in mistake rib. It would make a nice scarf, and there are lots of examples in Ravelry. (It is reversible of course - every row is the same.) But I have plenty of scarves - something different would be good.