setLayout( new GridBagLayout() );
constraints.weightx = 1.0;
constraints.weighty = 1.0;
constraints.fill = GridBagConstraints.BOTH;
int x, y; // for clarity
addGB( new Button("North"), x=1,y=0 );
addGB( new Button("West"), x=0,y=1 );
addGB( new Button("Center"), x=1,y=1 );
addGB( new Button("East"), x=2,y=1 );
addGB( new Button("South"), x=1,y=2 );