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Comment by typomatic | Hacker News Reader

This is Unruly from Simon Tatham's puzzle collection: http://www.chiark.greenend.org.uk/~sgtatham/puzzles/

I install this on literally every device I own. Windows machines, linux machines, android machines. It's a great source of small, procedurally generated puzzles. I often just put on some music and zone out playing Pearl for a while.

e: If you're on Ubuntu: sudo apt-get install sgt-puzzles

e2: I misremembered, it's not precisely Unruly--Unruly allows you to repeat rows/columns. But whatever, go install these games!

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That collection is technically kind of interesting too. The puzzle code itself is written in portable C, using a custom-built common framework and UI abstraction layer that allows it to run on pretty much any platform.

http://www.chiark.greenend.org.uk/~sgtatham/puzzles/devel/

Also, each puzzle has its own custom constraint solver to generate fresh puzzles with desirable characteristics. For example, the version of minesweeper in the collection generates puzzles such that the first click never reveals a mine and that there is always a logical path to the solution -- no guessing needed.

I always wonder with these kinds of puzzles how one can come up with an initial settings that (a) yields a unique correct solution and (b) has a logical next step at every step (so doesn't require thinking ahead x steps to arrive at a conflict)

One possibility is to generate or change small parts of the puzzle each turn. For minesweeper for example you start out with an empty field, and after the first click you generate the mines.

Conveniently enough, there's a long section of the developer docs that covers exactly that topic: http://www.chiark.greenend.org.uk/~sgtatham/puzzles/devel/wr...

For at least Loopy, the generator works by generating a full puzzle with all hints, and then removing hints one at a time until the solver can't solve the puzzle. So the complexity of the puzzles that can be generated are dependent on the cleverness of the solver.

That's less elegant than I hoped for. Still works though!

This almost seems like something you'd see in a thedailywtf article.

Want to write an application that does X? Design, build, test, and document a flexible cross-platform framework that can safely and portably run any application in the domain, and then specialize it to do X!

I have to say, though, that it seems to have actually worked out for the best in this case. He added a ton of puzzles at a rapid pace and they've spread to a surprising number of platforms.

And now maybe you understand why "flexible cross-platform frameworks" are not automatically a WTF ;)

Oh wow. These were installed on all the computers at school. We would often have hours where we didn't have any lessons scheduled, but couldn't play games, watch YouTube or go on Facebook as we would get our accounts suspended. This was the only game we could play as we could argue that it was technically "learning". The other one was a website where you had to name and locate all states in the USA. We are a British school.

If you choose a custom board size for Unruly, it also lets you choose the option to make rows/columns unique. This slows down the generation.

This is also the same as the Landscaper puzzles in the Logic Games iOS app (https://itunes.apple.com/us/app/70-logic-games-time-killers/...)

Unruly has an option to enforce unique rows & columns.

This just killed my productivity and made my day.

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