An exercise for implementing a backtracking recursive algorithm.

• use main(); on browser console to solve the sudoku seed that is at the moment hardcoded to main.js

• Add HTML/CSS visualization for the solution, instead of the raw text formating
• Add a way for player to input the solution and DOM handling for submitting. The submit should check against the solved grid and inform the player.
• Add a way to create "new" puzzles by manipulating seeds:
  • Rotate the matrix 1-3 times.
  • Mirror against the centerlines.
  • Map all numbers to other numbers ie. 1 <-- swap all --> 3.
  • Shuffle any 2-3 rows or columns that span the same 3 boxes.
  • Or a random combination of these
• Add more seeds with varying degree of difficulty (easy - medium - hard), allow user to generate new puzzles based on UI selection.