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