public void paintComponent(Graphics g) { // Draws content in the panel
        // Prepare panel for drawing
        super.paintComponent(g);
        int w = getWidth();
        int h = getHeight();
        int incrementX = (w - 2 * startX) / (lines - 1);
        
        for(int lineNumber = 0; lineNumber < lines; lineNumber ++) {
        	g.drawLine(startX + lineNumber * incrementX, startY, startX + (lines - 1 - lineNumber) * incrementX, h - startY);
        }
    }