public void mousePressed(MouseEvent e)
		{
			int x = e.getX();
			int y = e.getY();
			int column = x /( WIDTH / numColumns);
			int row = y /( HEIGHT / numRows);
			if(!cellWorld.isCellAlive(row, column))	{
				cellWorld.setCellAlive(row, column);
			} else {//cell is already alive, so set it to dead
				cellWorld.setCellDead(row, column);
			}
			repaint();
		}