These things can be divided into isotopy classes and expressed in orthogonal array representation.
One of these things comprises the coat of arms of the Statistical Society of Canada. A stained-glass window in Caius College, Cambridge depicts one of these and honors Ronald Fisher, whose work Design of Experiments used   these things for experimental design. McKay and Rogoyski, in a 1995 paper, counted the number of these things with order 10 and higher. These things can be divided into isotopy classes and expressed in orthogonal array representation. Solutions to   Kenken and Sudoku puzzles are examples of these things. For ten points, identify these n Ã— n arrays which contain every integer from 1 to n exactly once in each row and column.
One of these things comprises the coat of arms of the Statistical Society of Canada.
Latin squares [prompt on Sudoku solutions and Kenken solutions until they are respectively read]