Sudoku puzzle collections are published as books and are also printed in some newspapers and magazines. Sudoku puzzles can be found online (try a simple "sudoku" search) and are available for download on many mobile devices.
One might find free Sudoku downloads by going to the Web Sudoku website. The website has both online Sudoku games to play as well as downloadable games.
There are several places where one can play sudoku online. Some interactive online sudoku websites include Web Sudoku, Sudoku Saviour, and You Play. Sudoku puzzles can also be printed out and completed by hand, and these types of puzzles can also be found on these websites.
Pyramid sudoku is a regular sudoku board with shaded areas. Not only does one need to complete the regular sudoku, but the shaded areas can only have 1-9 as well.
There is only one way to correctly fill a sudoku.
Real sudoku puzzles require one solution to be complete. Most sudoku websites use an algorithm to create those one solution sudoku puzzles. You just can't fill an empty grid with random numbers because you can end up with multiple solutions. Here is a list of sudoku websites where you can play online or print sudoku puzzles : http://www.domo-sudoku.com http://www.websudoku.com http://www.sudoku.com http://www.dailysudoku.co.uk yes, but (like I was looking for) you cannot print your OWN puzzles!
Although Sudoku can be fun, it is not an activity that lends itself to "killer images". Try finding a friend interested in Sudoku and discussing interesting games.
One could visit SudokuProfessor or SudokuDragon to find strategies on how to complete a Sudoku Puzzle. Also, if one happens to have a Sudoku Puzzle Book, at the front page is usually a guide to how to complete a Sudoku puzzle. Once you know how to, they are really fun and good for keeping the mind active.
Yes
If you are referring to published Sudoku puzzles, the answer is No. These are generally designed to have exactly 1 solution. That fact can sometimes help solve a Sudoku by eliminating choices that create non-unique configurations. If you are asking about possible Sudoku boards, the answer is yes - there are many more possible sudoku puzzles with multiple solutions than with unique ones. Details and examples can be found at the related link.
"Eighty-one Squares in a Sudoku".
The puzzle known as "Al Escargot" (the snail) is currently considered the hardest Sudoku puzzle. It was created by a Finnish mathematician called Arto Inkala. One of the hardest Sudoku books available is "Extreme Sudoku" by Antoine Alary, not to be confused with "X-TREME Sudoku" by Nikoli & Co. or "Sudoku Xtreme" by Christopher Monckton, which are both an order of magnitude easier.
Traditionally Sudoku puzzles are 10 x 10 grids. These puzzles can be found in most broadsheet newspapers, in varying degrees of difficulty. Books of Sudoku can also be purchased from retailers such as Amazon.