Who would have thought that scribbling numbers into boxes could be so much fun - or so fiendishly addictive? Sudoku-mania has gripped the country. At the office and at school, on trains and on aeroplanes, at home and on holiday, we're all hooked. Satisfy your Sudoku cravings with these collections of puzzles from "The Independent". Deceptively simple, Sudoku puzzles are solved using logic alone. Just complete the grid so that every row, column and 3A-3 box contains the numbers 1-9.