anchor.diff:  
   
   /**
  - * Wraps the particle inside the given 3D box 
  + * Wraps the particle inside the given box shape
    */
   class BoxWrap extends Constraint<Particle3> 
   {
  
positive.code:   }
  }
  
  
negative.code: part of physics;
  
  /**
   * Keeps the particle inside the given box shape
   */
  class Box extends Constraint<Particle3> 
  {
  