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The myth of the sudoku's

Sudoku's have been quite a hype in recent years, attracting puzzle lovers all over the world. I have solved quite a number of them myself, or at least, that's what I thought until earlier this year. Seeing the daily "difficult"/"superieur"-level sudoku in a Swiss free newspaper, a coin dropped. They've been publishing the same sudoku for over a year now. Yes, that's right, the same sudoku, every day. Or more precisely, an equivalent sudoku. By using four simple transformations, yesterday's sudoku can be transformed into today's, and so can the solution !
  1. rearranging rows withing the same 3-row block (idem with columns)
  2. rearranging the order of the 3-row blocks (idem with 3-column blocks)
  3. permutating 123456789 into a different order
  4. transposing the grid (making rows into columns and vice versa)
How long can they keep this up, you wonder ? There's a total of about 1.2x10E12 combinations to every sudoku puzzle. It will take them 4.6 billion years before they run out of variations of this "one and only" sudoku.

PS the title of this article refers to "the myth of the fingerprints" by Paul Simon. "I've seen them all and man, they're all the same..."


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