@Override
    public void paintIcon( Component c, Graphics g, int x, int y ) {
        g.setColor( Color.black );
        g.drawRect( x, y, size-1, size-1 );
        if( null == color ) {
            g.drawLine( x, y+size-1, x+size-1, y );
        } else {
            g.setColor( color );
            g.fillRect( x+1, y+1, size-2, size-2 );
        }
    }