Category: Sudoku Puzzles

Today I am applying the most popular and historically enduring card games using its playing cards to Sudoku. Card Games have been manual endeavors but have tapered off after the 1990s when PCs became sufficiently prevalent. Only since the advent of PCs has digital computer software been written to simulate card games, notably one player Solitaire based games which were a strong motivator of and user interface training, once the PC was available (in offices and homes!).

They are now supplanting physical card games, perhaps most due to the “(double) click” that properly places a card where it should go. This is infinitely more convenient and immeasurably speeds up the game compared with picking up a card and putting it where it belongs. I’m sure some people may “click” on principle just in case the software knows more than they can see (at 3AM).

My favorite visual humor involving Solitaire for the 80s and 90s is shown here.

One way to merge (really small) playing cards with a Sudoku board is to use velcro on all the cards and in each square. Your Sudoku (partial) solutions will persist much longer.

Some interesting Card Game sites include The House of Cards which has information and rules for many kinds of games involving playing cards as well as downloadable software and online versions of card games.

The Card Games Web Site has card and tile games from the world over as well as many links to other card game and card related sites.

Of course, Hoyle’s Games, Improved And Enlarged is a mainstay for Card game rules and mathematical analysis (of odds) since 1835.

Since card games have been around since before 1000 A.D., Where they are believed to have originated in Central Asia and spread to the Moslems and then to Europe and finally to the North and South America and Australia. Look at A Brief History Of Playing Cards” for many fascinating details about the playing card evolution, especially after 1800 in the United States.

The following site also has historical but not necessarily currently played card games:
Rules To Period Games

Thanks to all who are following my whimsical Cartoons involving Sudoku variants.

There is a continuing fascination with predecessor number systems like Roman Numerals. This Wikipedia site also discusses fractional notation and the subsequent use of the “zero” as N (standing for Null). There are sites which provide Arabic from/to Roman Numeral Converters and those that actually teach how to perform arithmetic operations using Roman numbers.

A little known function in Excel 2004 (maybe others) called roman(arabic_no,form) permits varying Roman Number succinctness. As the help facility notes: we have
0 for classic; 1, 2, 3 for more, more and more concise; and 4 for simplified. (Look up Excel Help for Roman form). In particular the number 499 has 5 (!) versions: CDXCIX, LDVLIV, XDIX, VDIV, and ID.

One of my favorite problems for Computer Programmers learning the C programming language (I taught this in the 1980s) was to write an Arabic to Roman Number Converter, using associative arrays of all the possible symbols as a preferred solution technique. It exercised many language aspects and involved arrays and pointers.

In this Sudoku variant, there is also no room for “small candidate” roman numbers, unless you use a classroom sized whiteboard. Reading clocks with Roman Numerals discloses that IV = IIII and that V, VI, VII and VIII are read while (they or you are) upside down. IV = IIII is done so that IV won’t be confused with an upside down VI, or so they say.

The ubiquity of Barcodes! They’ve come upon the scene suddenly in 1973 and for a while barcodes showed themselves in many inappropriate places (tattoos, cartoons, human foreheads, etc.), they became invisible because they were everywhere. Indeed, they are significantly missing from the educational curriculum. Mathematics ignores them. Ironically, the initial outcry was that human beings should not be treated merely as numbers!

New tagging inventions, particularly the Radio Frequency Identification (RFID) tagging technology were born invisible. The furor against this has been minimal, despite that an RFID tag can be applied to or incorporated into a product, animal, or person for the purpose of identification using radiowaves. Perhaps the mantra for humans could be: I am not a signal tag!

But I digress. I have taught Unix Shell Programming with a Final exam question that was 3 pages of Barcode introductory description and one paragraph of question, involving computing the check digit on bonafide and illegal barcodes.

In the case of this Sudoku variant, it’s clear that the usual solving methods won’t work as well since the graphic representation of the number takes up nearly the entire cell. Perhaps a parallel Sudoku must be solved with ordinary numbers and then the barcode transcription be made.

In any event, I thought this was a cool way to solve a Sudoku puzzle. I hope you enjoy the sight or the struggle.

This is a Unary Number System variation that is popular in China, Japan and Korea. The full Character (Cheng) means honesty or correct according to the Wikipedia Tally marks article.

Something I neglected to mention in the first Unary Sudoku Cartoon is the Encyclopedia of Integer Sequences which contains within it the table of the first 1000 Unary Numbers! This table was created by David Wasserman. While this is something of a non-computational table, it turns out to be really handy when you need to copy and paste the Unary number elsewhere, rather than count the strokes yourself.

For this week, I am indebted to a notice by Peter (of Belfast) from Sudokuworld Yahoo Group whose reference tosudoku.xls site has directions for standard text files useful for the visually impaired and blind. In Peter’s link, there are not only ordinary Sudoku puzzles but also Sudoku Tanto (Odd and Even clues) and 6×6 Mini-San Puzzles which overlap in the last/first block of cells.

A search of the key phrase “Blind Sudoku” yields Sudoku-Swicki which is a list of links related to “Braille Sudoku”. Also, Google Groups has The Blind Sudoku Discussion group. Fred’s Head Companion with the American Printing House For The Blind, is another site specializing in tips, resources, and a general database for and by blind and visually impaired people.