This is an example of a completed Quadruple Sudoku puzzle.
The usual rules of Sudoku apply, but the grid contains Quadruple clues - these are always centred in the middle of 4 cells.
All the numbers inside a Quadruple clue must be in the surrounding 4 cells.
Some Quadruple clues will contain the same number twice - this means it will need to appear twice
in the surrounding cells.
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How to play
