Free Sudoku. Sudoku is a logic-based, combinatorial number-placement puzzle.
There are three variations of Sudoku in this app:
- Classic Sudoku;
- Diagonal Sudoku;
- 4 difficulty levels
- unlimited number of puzzles
- autosave the current position
- editable pencil marks
The puzzle Proof of Quilt is one of many pencil-and-paper puzzles.
An instance of Proof of Quilt consists of an m × n rectangular board of unit squares. Each square is either white or black, and some black squares contain a number. A candidate solution to the puzzle consists of filling
in some of the white squares with a black half-square (isoscele…