The Sudoku story began in 1783 when Leonhard Euler, a Swiss mathematician, devised Latin Squares, which he described as a new kind of magic squares. Euler had come up with a grid in which every number or symbol appears once in each row or column. More than two centuries later, the difference for Sudoku players is that the grid is subdivided into blocks of nine. It can also be played in many formats such as electronic Sudoku, handheld Sudoku or puzzles in Sudoku books.