anchor.diff:      this.linearVelocity = linearVelocity;
       this.angularVelocity = angularVelocity;
       this.angularDampening = angularDampening;
  +
  +    this.allowSleep = allowSleep;
  +    this.awake = awake;
  +    this.fixedRotation = fixedRotation;
  +    this.bullet = bullet;
  +    this.active = active;
     }
   
     Object tag;
  
positive.code:       _body.angularDamping = angularDampening;
    }
  
    bool allowSleep;
  
    bool awake;
  
    bool fixedRotation;
  
    bool bullet;
  
    bool active;
  
    double gravityScale;
  
  
negative.code:     double angularVelocity: 0.0,
      this.linearDampening: 0.0,
      double awakeangularDampening: 0.0,
      bool allowSleep: true,
      bool awake: true,
      bool fixedRotation: false,
      bool bullet: false,
      bool active: true,
      this.gravityScale: 1.0
    }) {
      this.density = density;
  