private void addNewWormSprites() {
		Collection<Worm> worms = getFacade().getWorms(getWorld());
		if (worms != null) {
			for (Worm worm : worms) {
				WormSprite sprite = getWormSprite(worm);
				if (sprite == null) {
					createWormSprite(worm);
				}
			}
		}
	}