Wednesday, 26 October 2011

Puzzle #41: Country Road/Land and Sea

I liked the first one I made of these, so figured I'd give this combo another try. I think this one is a bit trickier than the previous one, but that could also be caused by the fact that this one took a lot more effort to get to work out in a way that I liked.
I haven't been able to combine Land and Sea with any other genre satisfactorily. I like it here because it replaces a clue type completely while in others it just comes over as merely an addition.

Rules for Country Road

Rules for Land and Sea

This one solves as a normal Country Road puzzle, with the addition that the loop can't run through more than 2 white squares consecutively.

[Edit: Fixed a uniqueness issue. Somewhat major, but quite easily fixed luckily]


  1. I like it.80% of it was very smooth.Overall,the Land and sea rule(more so because it was used for uniquness in the two 'P' shaped countries in the middle) was overshadowed by the basic country road rule which did most of the work here,with the 'L' -shaped tetromino in the top-edge.Another of the few easy puzzles on your blog.I am looking for something that combines both sets of rules uniformly.

  2. I don't really see how you can solve most this puzzle while ignoring the Land and Sea rule. It is necessary far more than for just the 2 P cell areas in the middle. I think almost all Country Road progression is instigated by a Land and Sea deduction.
    As this combination only uses the negative inference from the Land and Sea genre, most loop progression will be country road. It's impossible to use the all cells must be visited rule with Country Road.

  3. Correct.You can not visit all cells.I didnt mean that.I just felt i was mostly guided by the country road rule.It was just my experience.It does have nice deductions like the one in the 2x2 square in the top right corner.
    I tried to design one today, and i tried to satisfy myself a little more with the land and sea deductions.

  4. Can't, really. The finished loop has several spots that would become ambiguous without the Land and Sea rule. For example, the hexomino in the southwest quadrant wouldn't need two empty spaces, and those give pretty big clues.

    I was going to bring up the uniqueness issue, but I finally saw your edit. Progress went much better.

    As for how to combine L&S with a different second puzzle.... The main result of "no more than two whites" is that every (visited) white cell must be path-adjacent to a gray cell. So depending on whether every cell must be visited and what gray density you have, you get a lot of the path right there.

    If you keep those issues in mind, maybe Double Back will work. Both have the rule of visiting all cells, so that loosens the second rule of each. And Melon has already combined DB with CR, so some of the research in that area has been done.

  5. Yeah, I had thought of Double Back. I still have to see how to do it though. With Country Road I have just been putting down a pattern of Land and Sea and designing the Country Road around it. With Double Back that didn't seem to work very satisfactory.

    I think I like Country Road as it doesn't force you to visits all cells and you avoid many forced lines by the Land and Sea genre. I prefer the negative inference of Land and Sea over the positive.