Latin Square

The aim of this game is to add the coloured balls to the board so that no colour appears more than once in any row, column or diagonal. Select a ball by touching it. It will then be displayed in an enlarged form. Select the destination hole. If this is a valid move the ball will be moved there. To unselect a ball touch it again. The classical mathematical description of a Latin Square allows colours (or numbers) appearing more than once in diagonals. The solution to this puzzle does not allow this.