www.sachsentext.de

Change some digits in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9 and so that no pair of changed digits is horizontal or vertical adjazent (diagonally adjazent changed cells are allowed).

Change some digits in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9 and so that no pair of changed digits is horizontal or vertical adjazent (diagonally adjazent changed cells are allowed).

Change some digits in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9 and so that no pair of changed digits is horizontal or vertical adjazent (diagonally adjazent changed cells are allowed).

Turn 5 times a 3x3-box 90 degree to the left or right so that after that each row, column and 3x3-box has exactly one of each digit.