title: Unique methods to generate sudoku puzzle
body: <p>How many possible unique ways are there to generate a Sudoku Puzzle?? 
  I can think of only two possible ways
  1) Take a solved Sudoku puzzle and shuffle the rows and columns
  2) Generate a random number and check if it violates any Sudoku constraints, repeat untill number does not violate any Sudoku constraint for every square(theoretically possible but normally it leads to deadlocking )</p>
  
  <p>Are there any other ways?</p>