And that's one infinite family of solutions, one that I didn't (initially) find.
There are more.
Initially I had 5 actual solutions, and I thought I had them all. Then someone produced this infinite family, and I suddenly had my mind expanded. I've since found what I hope - but have not yet proved - is all solutions.
Can you find any more? You might not care, but that's the challenge. I find it akin to the best sort of programming, except it doesn't, in the end, actually do anything.