GridBagLayout: Direction of Addition (8)

   // btn5 right of btn4
   c.gridx = GridBagConstraints.RELATIVE;
   c.gridy = 2;
   gridbag.setConstraints(btn5, c);

   // btn6 below btn5
   c.gridx = 2;
   c.gridy = 3; // absolute, for variety
   gridbag.setConstraints(btn6, c);

   resize(400, 200);
   setVisible(true);
}