anchor.diff:  
   Many Spatials represent game characters or other entities that the player can interact with. The above code that rotates the two boxes around a common center (pivot) could be used for a spacecraft docked to a orbiting space station, for example.
   
  -Depending on your game, game entities do not only change their position, rotation, or scale (the transformations that you just learned about). Game entities also have custom properties, such as health, inventory carried, equipment worn for a character, or hull strength and fuel left for a spacecraft. In Java, you represent entity data as class variables, e.g. floats, Strings, or Arrays. 
  +Depending on your game, game entities do not only change their position, rotation, or scale (the transformations that you just learned about). Game entities also have custom properties, such as health, inventory carried, equipment worn for a character, or hull strength and fuel left for a spacecraft. In Java, you represent entity data as class variables, e.g. floats, Strings, or Arrays.
   
   You can add custom data directly to any Node or Geometry. *You do not need to extend the Node class to include variables*!
   For example, to add a custom id number to a node, you would use:
  
positive.code: 
  
  .  You create a second box Geometry.
  +
  **  Create a second Box shape with the same size.
  **  Position the second box at (1,3,1). This is straight above the first box, with a gap of 2 world units inbetween.
  **  Wrap the Box shape into a Geometry.
  **  Create a red material. 
  **  Apply the red material to the Box Geometry. 
  +
  [source,java]
  ----
  
negative.code: = jMonkeyEngine 3 Tutorial (2) - Hello Node
  :author:
  :revnumber:
  :revdate: 2016/03/17 20:48
  :keywords: beginner, rootNode, node, intro, documentation, color, spatial, geometry, scenegraph, mesh
  :relfileprefix: ../../
  