"Mathematicians do not study objects, but relations between objects." — Henri Poincaré
"Mathematicians do not study objects, but relations between objects." — Henri Poincaré
There are Sudoku variants with extra constraints: Killer Sudoku (cage sums), Diagonal Sudoku, and even 3D Sudoku.
There are Sudoku variants with extra constraints: Killer Sudoku (cage sums), Diagonal Sudoku, and even 3D Sudoku.