SBY is a PC-based Sudoku program that far exceeds the functionality of the typical puzzle-solving program. It not only comes with hundreds of puzzles and an electronic work sheet for solving, but also (1) comprises a database for adding new puzzles; (2) supports the printing of big solving grids with a built-in Options Grid; (3) introduces a revolutionary “degree of difficulty” rating system; (4) supports the importing and exporting of puzzl