A few times each year – once or twice a semester at Art Center, I get to explain to the uninitiated what a “variable” really is. Not the mysterious x from high school algebra, whose contents are unknown, and which we must decipher — even though there is no tangible reward! No, not an annoying mystery, but a comforting little pocket — one of many pockets, that we can put stuff in: quarters, gum, knives & marbles, for later retrieval.

I love introducing programming concepts to neophytes – it is why I teach. But I must admit, it’s a little daunting, and I’m not entirely successful at it. I figure at least half of my students are like the cook who learns to make a roux, but only uses it for the one dish for which it was initially required. They write down the recipes, but don’t really grasp the concepts.

But in each collection of the unilluminated, there are always a few “ahas”. And each time I hear an audible “aha!”, a thrill runs through me. I imagine the feeling is a little bit like the pleasure of converting the unsaved. Through the newly opened eyes of the convert, I see myself, years ago, when my own eyes were newly opened. I am young again, and feel the spark of new discovery.

I have transformed an enigma into a pocket.

If you’re interested in the puzzles on this website, and would like to learn more about what goes into making them, you may enjoy the article I wrote for this month’s Mung Being magazine, where I am the resident puzzle constructor.

The article amounts to a FAQ, or IAQ (infrequently asked questions) for the puzzle section. There is a little technical information at the end of the article for those attempting to write their own puzzle software.

Puzzle Building and the Creative Mind

Here ya go. More Slitherlink puzzles using the quasi-periodic 5-fold tiling by Sir Roger Penrose.

I’ve also added some new Slitherlink puzzles that use Laves tiling (named after Crystallographer Fritz Laves), which are my most challenging Slitherlinks yet.

Enjoy!

About 18 months ago, I was contacted by a publisher, Ulysses press, that wanted to put out some Kakuro books, and I provided enough puzzles for three books.

Like most small publishers, Ulysses was blindsided when the Sudoku craze hit, and didn’t manage to get any books in the pipeline before the market was glutted with Sudoku books. They were hoping to cash in on the “next Sudoku” and so were a lot of other publishers, including those that had already made a fortune on Sudoku, and were looking for more of the same.

A good place to look for the next Sudoku was Nikoli publishing, the Japanese publisher that popularized Sudoku. Nikoli’s second-most popular puzzle was Kakuro, so this seemed like a good candidate.

So by Christmas of 1996, there were a ton of Kakuro books on the shelves.

So, did the Kakuro gamble pay off?

I’m thinking “no”.

Last year at this time, my local Vroman’s bookstore had a floor to ceiling bookshelf devoted to Sudoku and similar puzzles, with two of those shelves devoted to the glut of Kakuro books that had just come out. There were about an equal number of books devoted to crossword puzzles, and poker was pretty popular too.

This year, however, while the huge number of Sudoku, Poker and Crossword books remains, those two shelves of Kakuro books are gone. In their place are just 5 volumes, mixed in with the Sudoku books. I’ve noticed a similar situation at the local Barnes and Noble as well.

Why is this? Well, there a few things to consider.

1) Sudoku’s popularity was fueled by its regular appearance in major newspapers. In the Los Angeles market, Kakuro does not appear in newspapers, so most local solvers are still unfamiliar with the puzzle. It’s interesting to me that a medium perceived as dying or “in trouble” plays a major role here.

2) The demand for puzzles follows a power curve, one of those “long tail” things, and Kakuro is definitely further down in the tail. Being a second place puzzle doesn’t mean you sell slightly less, it means you sell a lot less. My web logs show that the demand for Sudoku outstrips Kakuro about 10 to 1.

3) It is my belief that the majority of puzzle solvers are what I would call “comfort solvers” – they are not particularly anxious to try new puzzles out. If they find a puzzle they like, they stick to it for a good long while. Most of these solvers prefer easy and intermediate puzzles. Learning a new puzzle amounts to a “hard” puzzle. Comfort food it ain’t.

The Sudoku craze, I believe, will not be repeated for a good long while. Not in the puzzle arena. The last puzzle that achieved that kind of popularity was the venerable crossword.

I sure am liking these Slitherlink puzzles though, I must admit…

There’s a group over on Flickr called Mini Kaleids – Krazydad Style that collects images produced with one of my kaleidoscope toys (found on this very website).

The pool is up to 700 images, so I thought now would be a good time to build a Coverpop mosaic of all that eye candy. Here it is.

Ooh! Pretty!

Here’s a high-res version, suitable for printing, should you wish to make a poster or gift wrap or something…

On December 18th, 1987, the first version of the Perl programming language was released. You can learn more about it in this article over at Wired.

A lot of the visitors to this website assume my tool of choice is Flash, because that is one of the most visible things here, but in truth, a good deal of the content of my websites are produced in Perl. The puzzles are rendered with Perl scripts, the mosaics over at Coverpop, as well as much of my Flickr work are the result of Perl programs, and so on.

I still find myself gravitating to Perl, even though there are other more readable alternatives, such as Python and Ruby. It is probably the language I harbor the most affection for. To me, Perl is a lot like Felix the Cat’s magic bag. It’s not terribly attractive, but you can do an awful lot of things with it in very short order. It still amazes me what kinds of miracles that ugly bag is capable of producing!

Here are some new puzzles I’m working on.

These twelve Slitherlink puzzles use the aperiodic five-fold tiling discovered by Sir Roger Penrose. Not only are the puzzles pretty, but the tiling creates a variety of intersections, which makes the puzzles more interesting.

Download ’em here…

Thanks to Craig Kaplan for providing the dataset for the tiles!

I’ve been enjoying Slitherlink puzzles lately, and thinking about publishing some variations. Below is a Slitherlink puzzle on a Hexagonal grid I made recently. This tiling makes it more complex in some ways, and easier in others.

More importantly, from my point of view, it’s round. Always a good thing in my book.

Click the image to get a larger version.

Update: Here are a couple of new puzzles which use a Penrose tiling grid provided by Craig Kaplan:

Penrose Slitherlink 1

Penrose Slitherlink 2

Slitherlink is an addictive logic puzzle that was first published by Nikoli in Japan. The puzzle consists of a grid of dots, with some clue cells containing numbers. You connect horizontally or vertically adjacent dots to form a meandering path that forms a single loop or “Slitherlink.” The loop must not have any branches and must not cross itself. The clue numbers indicate how many lines surround the cell. Empty cells may be surrounded by any number of lines (from 0 to 3).

Now you can find hundreds of free Slitherlink puzzles on my puzzle pages.

If you’re looking for some tactics to help you get started solving these, check out this wikipedia tutorial.

Enjoy!

Thanks to Simon Tatham and Mike Pinna, whose source code I tweaked to generate these puzzles.

I’m working on some new puzzles and thought I’d give you a preview…

For the kids, I’m adding a new collection of mazes in a variety of animal shapes, such as this elephant.

For the non-kids, I’m adding some new logic puzzles, based on my favorites from Nikoli, the Japanese publisher that popularized Sudoku. One of those favorites is Slitherlink, which you can read more about, on Wikipedia.

Some of the software I’m using to generate these puzzles is based on Simon Tatham’s Portable Puzzle Collection, which contains a number of Nikoli puzzles. I modified Mike Pinna’s Slitherlink algorithm to produce symmetrical puzzles, which I prefer, and to minimize the number of clues per puzzle.

Sample Elephant Maze

Sample Slitherlink puzzles.