![A sudoku puzzle with a layout in the form of the numerals making 2020. Easy puzzle, fully soluble using cross-hatching Stock Photo - Alamy A sudoku puzzle with a layout in the form of the numerals making 2020. Easy puzzle, fully soluble using cross-hatching Stock Photo - Alamy](https://c8.alamy.com/comp/C1TJ0R/a-sudoku-puzzle-with-a-layout-in-the-form-of-the-numerals-making-2020-C1TJ0R.jpg)
A sudoku puzzle with a layout in the form of the numerals making 2020. Easy puzzle, fully soluble using cross-hatching Stock Photo - Alamy
![Is there a Sudoku app that automatically fills in the pencil marks? I usually spend 3-4 min filling in all pencil marks (boring) before starting to solve(fun!). I want the pencil marks Is there a Sudoku app that automatically fills in the pencil marks? I usually spend 3-4 min filling in all pencil marks (boring) before starting to solve(fun!). I want the pencil marks](https://i.redd.it/n0xr6qlcx3v31.png)
Is there a Sudoku app that automatically fills in the pencil marks? I usually spend 3-4 min filling in all pencil marks (boring) before starting to solve(fun!). I want the pencil marks
![Notre Dame researcher helps make Sudoku puzzles less puzzling | News | Notre Dame News | University of Notre Dame Notre Dame researcher helps make Sudoku puzzles less puzzling | News | Notre Dame News | University of Notre Dame](https://news.nd.edu/assets/80986/sudoku300.jpg)
Notre Dame researcher helps make Sudoku puzzles less puzzling | News | Notre Dame News | University of Notre Dame
The structure of a Sudoku puzzle instance (left), and its solution (right). | Download Scientific Diagram
![Pointing with a sudoku puzzle. This sudoku layout provides a downward facing arrow. The solution is on Alamy as BYC5RJ Stock Photo - Alamy Pointing with a sudoku puzzle. This sudoku layout provides a downward facing arrow. The solution is on Alamy as BYC5RJ Stock Photo - Alamy](https://c8.alamy.com/comp/BYC5RB/pointing-with-a-sudoku-puzzle-this-sudoku-layout-provides-a-downward-BYC5RB.jpg)