code: function setSceneProperty(sceneDrawGroup, tangramName, value) {
      if (tangramName.startsWith('outline:')) {
          if (sceneDrawGroup.outline === undefined) {
              sceneDrawGroup.outline = {};
          }
          sceneDrawGroup.outline[tangramName.slice(tangramName.indexOf(':') + 1)] = value;
      } else if (tangramName.startsWith('opacity:')) {
          sceneDrawGroup._hidden[tangramName] = value;
      } else {
          sceneDrawGroup[tangramName] = value;
      }
  }
docs: Sets a scene property, managing special cases (outlines and opacities)