Today's Mac timewaster is Dracosoft's Christmas Sudoku. I'm not usually a big fan of Sudoko, personally. I don't need to spend my free time looking at numbers in a grid. Isn't that what Excel is for? The folks at Dracosoft, though, replaced the traditional numbers with colorful Christmas icons. That I can get into. If you're already into Sudoku, the three levels of gameplay should provide hours of fun. If you're not hooked yet, this may just be the thing that drives you over the edge into obsession.

The price tag is $5.99, with a one-hour free trial.

Previous 12 Days of holidays downloads for OS X:
Day 1, Day 2, Day 3, Day 4, Day 5, Day 6, Day 7, Day 8

We have featured many a Sudoku game in the past few years, and here is yet another for Windows XP, aptly dubbed "Pure Sudoku." I like this one a bit. It is a free download, is fairly light-weight and features nice backgrounds and sounds that don't get in the way and aren't annoying. There are 43 different backgrounds that change automatically (if you care about that sort of thing), many difficulty settings, and over 20,000 puzzles to last you many years, or just one weekend if you are really bored and play really fast. Great for people who are snowed-in. The deluxe edition is only $9.99 (cheaper than most infomercials) and allows you to do more with Sudoku, like a hints feature, the ability to print puzzles, and 3X the number of backgrounds (woo-hoo) and much more. It is a fun little time-waster that already today I have found more addicting than I care to admit. Oops.

Thanks Mark for the tip!

I've fallen more or less out of my Sudoku obsession, but Sudoku Slam brings something new to the table. Sudoku Slam is a free web-based version of Sudoku, and has a "Traditional" mode that acts like most web-based Sudoku games. But it also has a "Sumo" mode that, for jaded, impatient Sudoku players like me, takes some of the tedium out of the game. Sudoku purists might call it cheating, but what Sumo mode does is automatically fill in all the "candidate" numbers at the beginning of the game and automatically eliminate candidates as you solve the puzzle. Sudoku Slam also has some other welcome features, like the ability to undo any mistakes you might have made, full keyboard control, and the ability to save and load games, as well as print them out. There's also a Smart Hint option in case you get stumped, and four different difficulty levels. Definitely worth checking out if other Sudoku sites have fallen short of your expectations.

Okay, time to really geek out. Declarative languages are really the way to go if you're trying to teach a computer how to solve a puzzle, and though Prolog is the king of the declarative playground, it's equally geeky to do it in SQL, and that's what Samuel Aina did. His article Solving Sudoku with SQL describes what his title suggests: finding the unique solution to a Sudoku puzzle using T-SQL in SQL Server 2000. While the code isn't short (compare to, e.g., Chris Neukirchen's Prolog version), it's very clear and well-commented and really shows off the power of declarative programming.

[Via Digg]

The Japanese-inspired numeric logic game is sweeping across the world. In many newspapers, a Sudoku puzzle grid sits alongside the traditional crossword and word search puzzles under the comics.  And downloadable versions of the addictive game are beginning to pop up.  The latest, and perhaps most refined, is Sudoku Companion from Verek.

This Macintosh app will help you to solve Sudoku puzzles or generate your own, ranging in difficulty from Easy to Fiendish to Insane. You can save your favorite puzzles and print them out, too.  Also, for those of you with the new Intel Macs, you'll be happy to know that Sudoku Companion is a universal binary, so it will cruise right along on your newer hardware.

I've featured super-addictive logic puzzle Sudoku as a Time Waster before, so it feels like cheating to mention it again, but I've found a great new Sudoku site called Iron Sudoku. While I'm still partial to the Miniclip.com version's mousewheel-driven interface, Iron Sudoku's non-Flash interface (yes, that's AJAX you smell) is easy to use and efficient enough for speed-players. It also has two different color markers, red and green (hold Shift or Ctrl, respectively) and lets you save your progress at any point (and I'm told autosave is coming soon). Most interestingly, Iron Sudoku is social software, so while you're playing you can chat with players around the world who are working on the same puzzle, and sometimes it's nice to know you're not the only one pulling your hair out hunting for hidden subsets. There's one puzzle per day and completing a puzzle wins you points—10 for Expert, 5 for Hard, and so on (but rankings unfortunately won't be enabled until April 1, unless I've been fooled). Signing up for Iron Sudoku is free, but paying members (a one-time $14.95 fee) get a few extra features like a friends list and account customization.

I first heard about Sudoku awhile ago, but never really got into it until this week. But boy did I get into it. Sudoku is a logic puzzle in which you're presented with a grid of nine rows and nine columns. The object of the game is to fit the numbers 1 through 9 into the grid so that each number appears only once in each row, column, and 3x3 sub-grid. At the beginning of the game you're given many of the numbers and have to use deductive to figure out where the rest go. It's a very simple game—sort of a cross between minesweeper and the venerable crossword puzzle—but maddeningly addictive and, at the higher difficulty levels (i.e. fewer "given" numbers), a real mental exercise.

There are many sites where you can play Sudoku online, but I've found Miniclip's Flash Sudoku  to be the best. It has three difficulty levels, the invaluable ability to record "guesses" (e.g when you know a cell must be a 3 or a 9, but you don't know which), and a new puzzle for each difficulty level every day.