//Clock
        SquarePanel squarePanel = new SquarePanel();
        squarePanel.setBounds(20, 20, 400, 400);
        getContentPane().add(squarePanel);


class SquarePanel extends JPanel {

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        
        
        setBackground(Color.WHITE);
        
        //Panel's size
        int panelWidth = getWidth();
        int panelHeight = getHeight();  
        int squareSize = Math.min(panelWidth, panelHeight) - 40;
        
        //Draw circle
        int squareX = (panelWidth - squareSize) / 2;
        int squareY = (panelHeight - squareSize) / 2;
        
        g.setColor(Color.BLACK);
        g.drawRect(squareX, squareY, squareSize, squareSize);
        
        int circleDiameter = squareSize - 20;
        int circleX = squareX + 10;
        int circleY = squareY + 10;
        g.setColor(Color.GREEN);
        g.drawOval(circleX, circleY, circleDiameter, circleDiameter);
        
        //Numbers
        g.setColor(Color.BLACK);
        g.drawString("12", squareX + squareSize / 2 - 5, squareY + 15);
        g.drawString("3", squareX + squareSize - 20, squareY + squareSize / 2 + 5);
        g.drawString("6", squareX + squareSize / 2 - 5, squareY + squareSize - 5);
        g.drawString("9", squareX + 5, squareY + squareSize / 2 + 5);
        
        // Get the center of the circle
        int centerX = squareX + squareSize / 2;
        int centerY = squareY + squareSize / 2;
        
        // Hour hand
        g.setColor(Color.BLUE);
        drawRhombus(g, centerX+35, centerY, 70, 20);
        
        // Minute hand
        g.setColor(Color.RED);
        drawRhombus(g, centerX-70, centerY, 150, 40);
        
    }
    //draw a rhombus shape
    private void drawRhombus(Graphics g, int centerX, int centerY, int width, int height) {
        int[] xPoints = {centerX, centerX + width / 2, centerX, centerX - width / 2};
        int[] yPoints = {centerY - height / 2, centerY, centerY + height / 2, centerY};
        
        int numPoints = 4;
        Polygon rhombus = new Polygon(xPoints, yPoints, numPoints);
        g.fillPolygon(rhombus);
    }
    @Override
    public Dimension getPreferredSize() {
        return new Dimension(400, 400);
    }
}