Fixed Second Window

           firstWindow.setTitle("Block Dodger Game!");

            Group root = new Group();
            Scene theScene = new Scene(root);
            firstWindow.setScene(theScene);

            Canvas canvas = new Canvas(550,700);
            root.getChildren().add(canvas);

            ArrayList<String> input = new ArrayList<String>();

        theScene.setOnKeyPressed(
            new EventHandler<KeyEvent>()
            {
                public void handle(KeyEvent e)
                {
                    String code = e.getCode().toString();
                    if ( !input.contains(code) )
                        input.add( code );
                }
            });
        theScene.setOnKeyReleased(
            new EventHandler<KeyEvent>()
            {
                public void handle(KeyEvent e)
                {
                    String code = e.getCode().toString();
                    input.remove( code );
                }
            });

                GraphicsContext gc = canvas.getGraphicsContext2D();

        Font theFont = Font.font( "Comic Sans MS", FontWeight.BOLD, 24 );
        gc.setFont( theFont );
        gc.setFill( Color.GREEN );
        gc.setStroke( Color.BLACK );
        gc.setLineWidth(1);

        Sprite cursor = new Sprite();
        cursor.setImage("cursor1.png");
        cursor.setPosition(200, 0);

        ArrayList<Sprite> triangleList = new ArrayList<Sprite>();

        for (int i = 0; i < 15; i++)
        {
            Sprite triangle = new Sprite();
            triangle.setImage("triangle1.png");
            double px = 350 * Math.random() + 50;
            double py = 350 * Math.random() + 50;
            triangle.setPosition(px,py);
            triangleList.add( triangle );
        }

        LongValue lastNanoTime = new LongValue( System.nanoTime() );

        IntValue score = new IntValue(0);

        new AnimationTimer()
        {
            public void handle(long currentNanoTime)
            {
                // calculate time since last update.
                double elapsedTime = (currentNanoTime - lastNanoTime.value) / 1000000000.0;
                lastNanoTime.value = currentNanoTime;

                // game logic

                cursor.setVelocity(0,0);
                if (input.contains("LEFT"))
                    cursor.addVelocity(-50,0);
                if (input.contains("RIGHT"))
                    cursor.addVelocity(50,0);
                if (input.contains("UP"))
                    cursor.addVelocity(0,-50);
                if (input.contains("DOWN"))
                    cursor.addVelocity(0,50);

                cursor.update(elapsedTime);

                // collision detection

                Iterator<Sprite> triangleIter = triangleList.iterator();
                while ( triangleIter.hasNext() )
                {
                    Sprite moneybag = triangleIter.next();
                    if ( cursor.intersects(moneybag) )
                    {
                        triangleIter.remove();
                        score.value++;
                    }
                }

                // render

                gc.clearRect(0, 0, 512,512);
                cursor.render( gc );

                for (Sprite moneybag : triangleList )
                    moneybag.render( gc );

                String pointsText = "Cash: $" + (100 * score.value);
                gc.fillText( pointsText, 360, 36 );
                gc.strokeText( pointsText, 360, 36 );
            }
        }.start();

        firstWindow.show();