Friday 25 September 2009

I Will - a.k.a. Friday Puzzles #15

This week’s entry in my Friday Puzzles series gets its own proper Radiohead-song-title because I’ve managed to go off on one and explored a few deeper avenues than I would have normally done.

Last week’s introduction to the Heyawake puzzle I have decided was a bit hard as an introduction to the puzzle – although I’m now confident it wasn’t totally unfair having had this feedback from one of the best nikoli.com solvers out there:
"I liked it! The start was simple enough, and then you made some medium-level deductions to get some big sets of blocks, etc. I’d say the grand finale (I felt pretty sure there were two solutions or more…no, I was wrong) isn’t as bad as you claim. It probably shouldn’t be someone’s first Heyawake, but it’s not the pinnacle of difficulty. It’s a harder medium, how’s that for a/n non-/answer?"
On the other hand, I’ve been having a little think about the nature of difficulty and the nature elegance within a puzzle. I think it’s fair to say that by no means are the two are correlated – see this entry for two examples of sudoku too hard to be elegant – well elegant for the pen and pencil solver anyway. To labour the point a little bit more, here is an example of a puzzle which is INSANELY difficult. If you solve it, the only logical deduction is that you used a computer:
I found that puzzle after routing around a forum discussion of the hardest sudoku puzzles, it has been given the slightly affectionate nickname “Platinum Blonde”. These people have gone way beyond the solving capabilities of any human solver. So whilst I may have claimed previously that the 2009 Zilina world record puzzle was as hard as it gets and that it’d be the puzzle Beelzebub himself would set you to save your soul – actually the behemoths these people whip up for each other you are doing extremely well to solve even if you use lots of trial and error. I recommend not even starting to attempt.

Now, on the other hand, some easy puzzles can be extremely elegant. Not necessarily in the techniques required to solve them in isolation, but how the techniques come together to form a complete and satisfying solve. What this could mean for example, is a puzzle that has a definite starting point, which leads directly to another deduction and so on – inducing a “continuous flow” to the solving experience. It may be a repetition of a particular solving technique, or it may be a particular visual pattern that emerges as you solve the puzzle. I guess much like any art form, there isn’t really a satisfying way to define what makes a beautiful puzzle – but even a complete novice can spot it and enjoy it when they see it.

Anyhow, that’s an awful lot to aspire to. I’m not quite sure how much of that I’ve managed to achieve with this Heyawake (if any at all), but I’m running out of time to fiddle with it today…
    #020 Heyawake – rated easy
All puzzles © Tom Collyer 2009

Sunday 20 September 2009

Friday Puzzles #14

So this week’s (last week’s?) puzzle was slightly delayed as I was concentrating on the nikoli sudoku time trial. My laptop was to have other ideas: deciding to delete/corrupt/mutilate/whatever a crucial windows system folder – and so I had to rush to a computer room to take part. Being all of a fluster, and starting a full minute late I managed a meagre 6th. Having gone back later, I improved upon my time by nearly two minutes. C’est la vie.

The upshot of all that is that I wanted to write my own fairly challenging sudoku – but I find writing Sudoku puzzles (or at least good ones) to be a lot more challenging than other nikoli puzzle types. So, cutting my losses for now, I’ve instead tried my hand at Heyawake. You can find the rules to the puzzle here.

I probably ought to have introduced the puzzle to my blog with a nice gentle introduction – but instead I’ve gone with a sink-or-swim puzzle where you’ll have to do a bit of thinking about the rules and their implications.
    #019 Heyawake – rated medium
All puzzles © Tom Collyer 2009

Friday 11 September 2009

Friday Puzzles #13

For a lovely sunny Friday afternoon, what could be nicer than to solve a couple of gentle Masyu puzzles? Well that sounded just a little bit too soporific for me, so I decided to spice things up with a little segregation. I give you all-white and all-black Masyu.

Note that you only really get great Masyu puzzles when whites and black are working in tandem – these I guess are more “concept” puzzles. Whatever that means. Still, if Tony’s reading I’m sure he’ll appreciate how wonderful and orderly these puzzles are.
    #017 Masyu – rated easy
    #018 Masyu – rated easy
 All puzzles © Tom Collyer 2009

P.S. You may be thinking that I’m a bit a bit of a casual racist – but if you wish to complain, I shall roll up my copy of the Daily Mail and beat you to death with it. So there.

Friday 4 September 2009

Friday Puzzles #12

So I’ve recently managed to get a reader hooked to the Nurikabe puzzle, which I am feeling quite pleased about because it is a rather nice puzzle. Thus far I have only really produced three of the Nikoli puzzle types (together with some variations upon their themes) – and I have been in two minds as to whether to branch out. This week the decision was placed into my own hands, as I got a bit lazy and so had to stick with something familiar.

However, having seen a link to a contest to publish a completely original puzzle, I have been having a think. In the works I’ve got something that manages to combine elements of Slitherlink with that of Nurikabe. More to come on that in the next few weeks.

Back to the here and now though, here’s a Masyu puzzle. I unsuccessfully tried to force in some global thinking into this puzzle; trying to nail down uniqueness invariably seemed to simplify things a little bit too much. Still, I’ve thrown in a little tributary “best of” Masyu tricks that I’ve seen on nikoli.com fairly recently. If you’ve seen these before, it’ll be possible to whizz through this in under a minute – 45s on paper from me to beat – if not there’ll be a couple of things you’ll need to think about.
    #016 Masyu – rated medium
All puzzles © Tom Collyer 2009

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