individual IOS developer has released best free sudoku app for iPad. some of key features include: 1. unlimited level. 2. 16 different beautiful theme background and colors can be chosen when you are playing the game. 3. instant visual hint available through the colors of red or green. 4. Play it anywhere you go, No internet connection or WIFI needed. How to play: Fill all the blank squares in a game with the correct numbers. There are three very simple constraints to follow. 1. Every row of 9 numbers must include all digits 1 through 9 in any order. 2. Every column of 9 numbers must include all digits 1 through 9 in any order. 3. Every 3 by 3 subsection of the 9 by 9 square must include all digits 1 through 9. Sudoku 3 version 1.3 is Free and available worldwide exclusively through the App Store in the Games category. http://itunes.apple.com/us/app/sudoku-3/id400473553?mt=8 Please rate, comment and make any suggestion of your thought about this game.