private void mainLoop() {
   mainController.timeStep();
   if (world.isGameLost()) {
     eventBus.fireEvent(new GameFinishedEvent());
     timer.cancel();
   }
 }
 private void initViews() {
   GemFieldView gemFieldView = new GemFieldView(BLOCK_SIZE, world.getGemField());
   mainView = new MainView(world, gemFieldView, BLOCK_SIZE);
   initWidget(mainView);
 }