Download free puzzle games for Windows, Linux and Macintosh
Get explanations of Sudoku, Kakuro and Minesweeper methods. See animations of Sokoban map solutions

Introduction

This site exists to make available a small collection of computer games - currently Sudoku, Kakuro, Sokoban and Minesweeper - and to provide explanations of methods to solve these classes of puzzles. The programs can be downloaded for free and are very easy to install on Linux and Windows. They are written in the languages Python and Tk and were used as exercises for learning the languages. The download includes the source code. This may be useful to other aspiring programmers, even if only to show how not to write Python and Tk. Creating the web site has also been a learning exercise: in this case learning the languages XHTML and CSS. Comments and suggestions about the programs and web site are very welcome.

Site navigation

The links at the top of this page will take you to the Downloads page or to the pages describing the individual programs. At present there are 24 pages on Sudoku, 20 on Kakuro, 9 on Sokoban and 7 on Minesweeper. For each of these sets of pages the "Next page" and "Previous page" links at the top and bottom of each page can be used to step through in sequence. The "Home" link will bring you back here and the "Program home" link will take you to the first page for each program. The site map page contains links to every section of the site and so can be used as an overview or a quick way to find the page you want.

A Sudoku Program SourGumdrop

SourGumdrop icon SourGumdrop is a Sudoku playing program that can help players learn techniques for solving puzzles. A typical screendump is shown below. SourGumdrop: version 0.5 example
A screen dump from SourGumdrop showing a Swordfish hint. The pattern of candidate 8's found and shaded in green allows the removal of the candidate 8's coloured in red.

A Kakuro Program SourGumdropK

SourGumdropK icon SourGumdropK is a Kakuro/Cross sum program with a wide range of hint methods and pop-ups to show the combination lists for all sums. A typical screen dump is shown below. SourGumdropK: example screendump
A screen dump from SourGumdropK showing a hint for method "UC" and a pop-up listing the possible combinations for the sum 9 in 2 cells. The hint has identified that the candidates shaded red can be removed.

A Sokoban Program Sourkoban

Sourkoban icon Sourkoban is a Sokoban playing program that can show animations of the solutions for all of its built-in maps and which remembers your solution for all puzzles. It also contains a graphical map editor/creator. A typical screen dump is shown below. Sourkoban: a typical view of the program
A typical view of the program. The man, represented by a Maltese cross, must push the marbles into the green circles. The Toolbar at the top controls movement between map sets, map levels, undo, redo, restart, replay, show solution. The File menu gives access to alternative ways of selecting maps, of reading and saving maps and solutions and setting various modes of operation. The status bar at the bottom provides simple statistics on the users progress.

A Minesweeper Program Minestein

Minestein icon Minestein is a Minesweeper program that produces puzzles which can be solved entirely by logic and which have a user defined minimum difficulty rating. It also has a two stage hint system to help beginners. A typical screendump is shown below. Minestein example
A screen dump from Minestein showing a hint. The question mark at row 7, column 7 is directing the users attention to a cell that must be a mine (because the 2 at 6,6 is touching one cell flagged as a mine and only one hidden cell - the cell at 7,7).

Licensing and source code

The programs are written in the Python language and are distributed as source code under the GNU General Public License. This means that you can redistribute them and/or modify them as long as you include the source code.

Do not worry that the programs are distributed as source code: Python programs are interpreted as they run so no compilation is required. Installation couldn't be easier: just download the source file and the programs are ready to run (assuming you have the Python libraries and interpreter installed).

The web site includes notes about the source code and the algorithms used by SourGumdrop and SourGumdropK.

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Tips on solving Sudoku puzzles

SourGumdrop icon These pages explain the methods for solving Sudoku puzzles and displayed as hints by SourGumdrop including: Simple filter, Singles, Hidden singles, Hidden pairs, Hidden triples, Locked candidates 1, Locked candidates 2, Naked pairs, Naked triples, Naked quads. Xwing, Swordfish and Jellyfish

Tips on solving Kakuro puzzles

SourGumdropK icon These pages explain the methods for solving Kakuro puzzles and displayed as hints by SourGumdropK.

Learn how to solve Sokoban problems

Sourkoban icon This page describes a way of using Sourkoban to learn how to solve Sokoban maps.

Learn how to solve Minesweeper puzzles

Minestein icon This page describes Minestein's hint mechanism. And this page shows a worked example of how to solve a Minesweeper puzzle.

Comments and feedback

This website exists to make the programs available, to act as a source of information to help people learn how to solve the puzzles, and to enable others to contribute ideas and suggestions on improving both the programs and the website. So, please send your comments: provide the stimulus to improve the programs and help to make them better for yourself and others. To increase awareness of SourGumdrop please link to sourgumdrop.org.uk from your site.

The email address for comments is:

Downloads

download icon The programs are available as free downloads. All the programs run on XP and Linux but only Sourkoban works on the Macintosh. Information about obtaining the programs and the source code is in the Downloads section.

News

June 19th 2009

Python 3.0 was released recently. This breaks the programs because of the change to the print syntax. Users must install Python 2.6 otherwise the programs will not run. Thanks to Emile who emailed to point this out.

December 8th 2008

Version 0.03 of Minestein released: Expert mode logical puzzle creation time greatly reduced: it now takes 1/260 of the original time!

December 1st 2008

Version 0.02 of Minestein released: halved the time taken to generate puzzles that can be solved by logic - though it is still too slow for large grids with many mines. (Please see December 8th 2008).

November 1st 2008

Minestein a Minesweeper program released for the first time. Please report bugs and suggestions for improvements.

October 26th 2008

Python version 2.6 was released recently and unfortunately it contains a bug which broke SourGumdropK. This new version of SourGumdropK (v1.02) provides a workaround for that bug and also improves some of the related code. Though a workaround it is a permanent solution. Testing with 2.6 has shown that when Python moves to 3.0 the programs should all work.

October 7th 2008

New version (v1.01) of the Kakuro program SourGumdropK released. Fixes bugs in the parsing of external puzzles and the uniqueness check.

August 21st 2008

Noticed that Gordon Royle now has 47793 17 clue Sudoku puzzles so redid my statistical analysis.

July 31st 2008

Reorganised the website and switched to using zip files for downloads. The zip files contain the source code and an icon file for each program. A single page now handles all downloads but the original download pages have been left on the site to satisfy external links. PAD files are now available in the ./pad directory. All program version numbers upped to 1.0. Thanks to kls for the pretty new banner and the gumdrops.

July 2nd 2008

Sourkoban v0.04 released. Bug fix: undo, redo did not update the move counter. In fixing this I removed the count of the number of pushes.

May 30th 2008

Sourkoban v0.01, a Sokoban program released.

April 20th 2008

SourGumdropK v0.02 released. Added the cell count and the sum to the pop-up menus which provide the row and column combination lists. Added configuration options.

April 16th 2008

SourGumdrop v0.64 released. Search strategy selection not working. Fixed.

April 10th 2008

SourGumdropK v0.01, a Kakuro program based on SourGumdrop released.

April 3rd 2008

Version v0.63 released. The default hint search strategy is now "simplest hint". The main change this release is embarrassing. While working on SourGumdropK, a Kakuro program, based on SourGumdrop, I noticed that the SourGumdrop puzzles had, at some stage, lost their difficulty ratings. This has been rectified. Please note that the prefered contact email name has now changed to rodg.

January 30th 2008

Version v0.62 released. Norman Hall requested the ability to group algorithms and to have a hint search strategy to find the simplest hint. He also wanted more control over the amount of information displayed about hints. His encouragement also got me round to adding the ability to save and read partially completed puzzles with their candidates. The "?" button in the Toolbar can now be used to execute hints (i.e. delete the candidates found) which means I can now click through a whole puzzle without moving my mouse - useful for testing! This latter change is not reflected in some screendumps used in the website. All these additions have been made and the documentation updated accordingly.

January 1st 2008

Ian Millington The R'n'D Guy pointed out that my locked candidate 1 figure was ill chosen so I've replaced it. Thanks.

May 19th 2007

SourGumdrop v0.60 released. Sudoku16 and Sudoku4 now possible: ie 16x16 and 4x4 grids. See: Alternative grid sizes

May 13th 2007

SourGumdrop v0.54 released. Since v0.5 I have tidied up the configuration code, fixed a bug in which the wrong causes were shown for hidden triples, and another in the directed guessing solver. Added the option to colour candidates using the middle mouse button. Thanks to all those reporting bugs. None known at present.

April 30th 2007

SourGumdrop v0.5 released. This is a complete rewrite of the program. New features: simpler, cleaner default look, but with a new configuration option which enables users to alter almost every component of the interface; new hint levels including the ability to show the candidates which form the pattern; simpler menu arrangements; timer; bug found and fixed in swordfish and jellyfish.