You are given a class similar to the TicTacToe board in Section 7.6, but the board can have more than 3 rows and columns.

Your task is to complete a method that fills the two diagonals with asterisks, like this:

*      *
 *    * 
  *  *  
   **   
   **   
  *  *  
 *    * 
*      *