anchor.diff:    final Scene scene_pnc = Scene("", pnc, [perspective]);
     phase.add(scene_pnc);
     theNodes.icoSmall = Node(
  -      "sphere", ShapeIcosahedron(scene_pnc.program, subdivisions: 4), material);
  +      "sphere",
  +      ShapeIcosahedron(scene_pnc.program, subdivisions: 4, scale: 0.1),
  +      theNodes.material)
  +    ..enabled = false;
     scene_pnc.add(theNodes.icoSmall);
   
     // =========================================
  
positive.code:   theNodes.icoBig = Node(
        "sphere",
        ShapeIcosahedron(scene_pncb.program, subdivisions: 3, scale: 500),
        material)
      ..setPos(0.0, 0.0, 0.0);
    scene_pncb.add(theNodes.icoBig);
  
    // =========================================
  
negative.code:   theNodes.knot = Node(
        "knot",
        ShapeTorusKnot(scene_pnvc.program, segmentsR: 512, segmentsT: 64),
        theNodes.material)
      ..enabled = false;
    scene_pnvc.add(theNodes.knot);
  
    // =========================================
  