Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. Equal digits can be neither orthogonally nor diagonally adjazent.

Fill in the grid the digits 1 through 7 so that no row, column, and diagonal contains any digits more then once. Different colors help to spot the diagonals.

Fill in the grid the digits 1 through 7 so that no row, column, and diagonal contains any digits more then once. Different colors help to spot the diagonals.

Fill in the grid the digits 1 through 7 so that no row, column, and diagonal contains any digits more then once. Different colors help to spot the diagonals.

Fill in the grid so that every row and every column contains each digits 1 through 5 exactly once. Starting from the left bottom corner there must be along the spiral the number order 1 - 2 - 3 - 4 - 5 - 1 - 2 - ... - 4 - 5.

Fill in the grid so that every row and every column contains each digits 1 through 5 exactly once. Starting from the left bottom corner there must be along the spiral the number order 1 - 2 - 3 - 4 - 5 - 1 - 2 - ... - 4 - 5.

Fill in the grid so that every row and every column contains each digits 1 through 5 exactly once. Starting from the left bottom corner there must be along the spiral the number order 1 - 2 - 3 - 4 - 5 - 1 - 2 - ... - 4 - 5.

Fill in the grid so that every row and every column contains each digits 1 through 5 exactly once. Starting from the left bottom corner there must be along the spiral the number order 1 - 2 - 3 - 4 - 5 - 1 - 2 - ... - 4 - 5.

Fill in the grid so that every row and every column contains each digits 1 through 5 exactly once. Starting from the left bottom corner there must be along the spiral the number order 1 - 2 - 3 - 4 - 1 - 2 - ... - 3 - 4.

Fill in the grid so that every of the nine marked 3x3 box contains the digits 1 through 9. No digit can repeat in a row or column.