private void drawEmptyGrid(Graphics g) {
		g.setColor(Color.BLACK);
		for (int i = 0; i <= nbRows; i++) {
			for (int j = 0; j <= nbColumns; j++) {
				g.drawLine(caseHeight * i, 0, caseHeight * i, nbColumns
						* caseHeight + 1);
				g.drawLine(0, caseWidth * j, nbRows * caseWidth + 1,
						caseWidth * j);
			}
		}
	}