A Sudoku board.

1. $ git clone git@github.com:slate71/sudoku.git
2. $ cd sudoku
3. $ npm install
4. $ npm start
5. Open localhost:3000 in a browser.

References

Designing a Sudoku Puzzle , by Moriel Schottlender
An article on Medium about Recursion
Wikipedia: Sudoku , Backtracking
stackoverflow