Sudoku is a Japanese logic game that exploded in popularity in 2005.

GNOME Sudoku was originally programmed in Python by Thomas Hinkle, though it has since been rewritten. It is meant to have an interface as simple and unobstrusive as possible while still providing features that make playing difficult Sudoku more fun.

Siffofin:

• The board and numbers automatically resize when you resize the window.
• The game is easily navigable from the keyboard — you can use arrow keys to move around and then just type the number to fill in the board.
• The game is easily playable with the mouse. Clicking on a square will highlight it. Clicking on the square again will show you a grid with the numbers 1 through 9; you can just click on a number to choose it.
• You can add notes or “earmarks” to squares easily by right-clicking, or with the keyboard by tying a number while holding Control.