      this.floatingCrystal = new FloatingCrystal();
                this.add(this.floatingCrystal);

                this.abstractCube = new AbstractCube();
                this.add(this.abstractCube);
            }

            // Public methods

            update = time => {
                this.darkPlanet.update(time);
                this.floatingCrystal.update(time);
                this.abstractCube.update(time);
            };

            ready = () => Promise.all([
                this.darkPlanet.