public PuzzleCell CheckRight(int myNum = 0)
 {
     CheckTimes = myNum;
     if (edgeRight || goalCell)
     {
         return(this);
     }
     else if (cellRight.occupied)
     {
         return(this);
     }
     else
     {
         myNum++;
         return(cellRight.CheckRight(myNum));
     }
 }