Sudoku

It's very simple yet challenging game.

Rules:

1) every row and column can have 1 to 9 numbers without repeating

2) there are nine 3X3 boxes, and each sub-box must have 1 to 9 without repeating



I use two different colors (blue and black) to distinguish each sub-box.

It is good to avoid duplicate numbers in any row, column, or sub-box; therefore, the game will give you a warning and does not allow a player to insert an invalid number in any block.

Please leave feedback and suggestion so I can improve and make it better.

enjoy the game



thank you