Hi I have invented the new sudoku you can download it from www.rainboku.com
It has the same logic rules as standard sudoku but has a nonagon board (similar to a hexagon but with 9 sides) and using colour rather than numbers. This game was invented last year by myself and has only been tested on 400 students (I am an I.T. teacher in England)All HAVE PREFERRED it to standard sudoku because it is so much more difficult. All students who have tested this beta version have been able to complete 17 number sudokus in less than 1 hour. The average time to complete one of my 9x9x9 is 2 hours and i give up to 30 given number/colour clues!!
please check it out and you will love it. it is a beta version and it is not advisable to download if your pc does not have windows 2000 or XP
regards
corin trivass