I've revived an old project involving Sudoku.

In theory, it should be possible to fill a blank grid based on any square number. Traditional puzzles use 9 symbols, and I'm sure I've seen hexadecimal puzzles before.

My program will, when finished, generate puzzles using the following options:

9 Symbols - 1-9

16 Symbols - 0-9, A-F

25 Symbols - A-I, K-Z

36 Symbols - 0-9, A-Z

Using a simple brute-force technique, I can fill a blank 9x9 grid within a few seconds, but the other grids don't seem to resolve. Here's my code so far. Given time, I will annotate it so that you know what it does.

http://fx.barcodebattler.co.uk/Sudoku.htmThe next step, once it can complete a blank grid properly, will be to remove some of the squares and generate a solvable puzzle.