// define a complex group of shapes.impl.composite
Builder builder = new CompositeBuilder();
builder.startGroup();
builder.addCircle(20);
builder.addRectangle(100, 200);
builder.startGroup();
builder.addRectangle(50, 30);
builder.addRectangle(300, 60);
builder.setFilled(false);
builder.startPolygon();
builder.addPoint(50, 50);