n (e) {
          switch (e.target) {
            case blueCube: {
              redSphere.setAttribute('visible', true);
              break;
            }
            case redSphere: {
              redSphere.setAttribute('visible', false);
              break;
            }
            case greenCylinder: {
              var oldVisible = greenCylinder.getAttribute('visible');
              // See issue: https://github.com/aframevr/aframe/issues/579
              if (oldVisible === null) { oldVisible = tr