Dominosa 26

[donkirkby]

In 2020, Michael Kragh Pedersen contacted me to ask if I'd seen any Dominosa problems that relied on the rotation of the pips to solve. I mentioned Catch 21, and we talked about how we could change my source code to understand rotation, but I didn't think it was worth adding another version of Dominosa to the collection.
Then recently, I had an idea: I could present the problems with one domino already outlined. Either the 23 domino or the 26 domino would show the rotation of 2, 3, and 6. Having one domino outlined would also allow for more interesting solution paths, avoiding the slow start of finding a unique pair.
Now that I'm publishing the book collection, I could add a Dominosa variant to start the second collection.