public void third() {

    // ! [3]
    QGraphicsScene scene = new QGraphicsScene();
    QGraphicsView view = new QGraphicsView(scene);
    view.show();

    // a blue background
    scene.setBackgroundBrush(new QBrush(QColor.blue));

    // a gradient background
    QRadialGradient gradient = new QRadialGradient(0, 0, 10);
    gradient.setSpread(QGradient.Spread.RepeatSpread);
    scene.setBackgroundBrush(new QBrush(gradient));
    // ! [3]
  }