this.setBackground(Color.white); // This component is white
this.setFont(new Font("Dialog", Font.BOLD, 24));
JPanel p1 = new JPanel();
p1.setBackground(new Color(200, 200, 200)); // Panel1 is darker
this.add(p1); // p1 is contained by this component
p1.add(new JButton("#1")); // Button 1 is contained in p1
JPanel p2 = new JPanel();
p2.setBackground(new Color(150, 150, 150)); // p2 is darker than p2
p1.add(p2); // p2 is contained in p1
p2.add(new JButton("#2")); // Button 2 is contained in p2
JPanel p3 = new JPanel();
p3.setBackground(new Color(100, 100, 100)); // p3 is darker than p2
p2.add(p3); // p3 is contained in p2
p3.add(new JButton("#3")); // Button 3 is contained in p3
JPanel p4 = new JPanel();
p4.setBackground(new Color(150, 150, 150)); // p4 is darker than p1
p1.add(p4); // p4 is contained in p1
p4.add(new JButton("#4")); // Button4 is contained in p4
p4.add(new JButton("#5")); // Button5 is also contained in p4
this.add(new JButton("#6")); // Button6 is contained in this component
