# Solo

You have a square grid, which is divided into as many equally sized sub-blocks as the grid has rows. Each square must be filled in with a digit from 1 to the size of the grid, in such a way that

* every row contains only one occurrence of each digit

* every column contains only one occurrence of each digit

* every block contains only one occurrence of each digit.

* (optionally, by default off) each of the square's two main diagonals contains only one occurrence of each digit.

You are given some of the numbers as clues; your aim is to place the rest of the numbers correctly.

Under the default settings, the sub-blocks are square or rectangular. The default puzzle size is 3×3 (a 9×9 actual grid, divided into nine 3×3 blocks).

# Controls

Use joystick buttons to move cursor.

If you press "OK" and then type a number, that number will be entered in the square as a ‘pencil mark’. You can have pencil marks for multiple numbers in the same square. Squares containing filled-in numbers cannot also contain pencil marks.

The game pays no attention to pencil marks, so exactly what you use them for is up to you: you can use them as reminders that a particular square needs to be re-examined once you know more about a particular number, or you can use them as lists of the possible numbers in a given square, or anything else you feel like.

To erase a single pencil mark, move cursor to the square, press "OK", and type the same number again.