Each puzzle consists of a 16x16 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 16 appear exactly once in each row, column, diagonal and 4x4 box.

The puzzle a 16 x 16 grid made up of 4 x 4 subgrids (called "regions"). Some cells already contain numbers, known as "givens". The goal is to fill in the empty cells, one number in each, so that each column, row, and region contains the numbers 1 through 16 exactly once. Each number in the solution therefore occurs only once in each of three "directions", hence the "single numbers" implied by the puzzle's name.

The puzzle a 16 x 16 grid made up of 4 x 4 subgrids (called "regions"). Some cells already contain numbers, known as "givens". The goal is to fill in the empty cells, one number in each, so that each column, row, and region contains the numbers 1 through 16 exactly once. Each number in the solution therefore occurs only once in each of three "directions", hence the "single numbers" implied by the puzzle's name.

The puzzle a 16 x 16 grid made up of 4 x 4 subgrids (called "regions"). Some cells already contain numbers, known as "givens." The goal is to fill in the empty cells, one number in each, so that each column, row, and region contains the numbers 1 through 16 exactly once. Each number in the solution therefore occurs only once in each of three "directions," hence the "single numbers" implied by the puzzle's name.

Each puzzle consists of a 16x16 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 16 appear exactly once in each row, column, diagonal and 4x4 box.

The puzzle a 16 x 16 grid made up of 4 x 4 subgrids (called "regions"). Some cells already contain numbers, known as "givens". The goal is to fill in the empty cells, one number in each, so that each column, row, and region contains the numbers 1 through 16 exactly once. Each number in the solution therefore occurs only once in each of three "directions", hence the "single numbers" implied by the puzzle's name.

Each puzzle consists of a 16x16 grid containing given clues in various places. The object is to fill all empty squares so that the numbers 1 to 16 appear exactly once in each row, column, diagonal and 4x4 box.