Soduktile is an online drag'n'drop patterned tile variation of Sudoku or Su Doku, or often incorrectly Soduko, an addictive brainteaser logic puzzle that has reached huge international popularity in the early 21st century. The puzzle is made up of a 9x9 grid with some of the 81 positions prefilled with a digit in the range 1 to 9. The supplied digits are sufficient to allow you to work out the missing digits through logic alone, without guessing. Each puzzle has only one solution. There is only one rule :- Each row, column and 3x3 section or block (as shaded in the example below) may have only one of each digit.

4								9		4	7	1	2	5	6	8	3	9
		9				7				6	8	9	1	3	4	7	2	5
	3		7	8	9		1			2	3	5	7	8	9	4	1	6
		7	5		8	2				9	1	7	5	6	8	2	4	3
		4				6				3	5	4	9	7	2	6	8	1
		6	3		1	5				8	2	6	3	4	1	5	9	7
	9		6	2	7		5			1	9	8	6	2	7	3	5	4
		2				1				5	6	2	4	9	3	1	7	8
7								2		7	4	3	8	1	5	9	6	2
puzzle										solution

The digits used in Sudoku are incidental; any symbols can be used. Soduktile uses colourful patterned symmetric tiles, randomly chosen for each user from a library of thousands. On successful completion of a puzzle, a player is given the opportunity of changing one tile pattern for a new one, so you're not stuck with any that you think are ugly. By using patterned tiles, the illusion of Sudoku being a puzzle involving arithmetic calculation is removed, and the game is opened up to a wider audience. Tiles are moved around the screen by dragging and dropping them on a board containing the puzzle, and therefore no typing is needed. In using arbitrary tiles, the puzzle is seen in a more holistic and aesthetically pleasing way. The whole playing area can be resized to fit your screen space with a zoom in/out function. Besides the traditional 9x9 (3x3 block) puzzles, Soduktile also offers more complex puzzles in 16x16 (4x4 block) and 25x25 (5x5 block) grid formats.


There are 6670903752021072936960 possible solution grids in the 9x9 format, or 18383222420692992 if we eliminate those that are equivalent through permutation, but the number of possible puzzles is far larger as each solution grid can be made into a huge number of different puzzles. All Soduktile puzzles are generated totally randomly as they are needed, and no puzzles are kept, so the chance of you ever getting one that you have previously seen is tiny.