anchor.diff:      wallsCollision.collider1 = ballbody.collider;
       wallsCollision.collider2 = world.collider;
       wallsCollision.onCollision.listen((event) {
  -      if (event.delta.normalized().x != 0.0 && event.delta.normalized().y != 0.0) {
  -        print("walls ${event.delta}");
  +      ballbody.position.add(event.delta);
  +      if (event.delta.x != 0.0) {
  +        ballbody.speed.reflect(new Vector2(event.delta.x.sign, 0.0));
         }
  -      ballbody.position.add(event.delta);
  -      ballbody.speed.reflect(event.delta.normalized());
  +      if (event.delta.y != 0.0) {
  +        ballbody.speed.reflect(new Vector2(0.0, event.delta.y.sign));
  +      }
         ballbody.syncToNode();
       });
       world.collisions.add(wallsCollision);
  
positive.code:       ..runAction(controller2);
  
      var ballbody = new ArcadeBody()
        ..speed = new Vector2(-300.0, 400.0)
        ..restitution = new Vector2(1.0, 1.0)
        ..addTo(world);
  
  
negative.code:     body2.collider = new AABB2Collider();
      body2.collider.body = body2;
      var paddle2Collision = new StaticBodyVsBodyCollisionCheck()
        ..collider1 = body2.collider
        ..collider2 = ballbody.collider;
      paddle2Collision.onCollision.listen((event) {
        ballbody.position.add(event.delta);
        ballbody.speed.reflect(event.delta.normalized());
        ballbody.syncToNode();
      });
      world.collisions.add(paddle2Collision);
  
      var paddle1wallCollision = new StaticBodyOutOfBoundsCollisionCheck()
        ..collider1 = body1.collider
        ..collider2 = world.collider;
  
      paddle1wallCollision.onCollision.listen((event) {
        body1.position.add(event.delta);
        body1.syncToNode();
      });
  
      var paddle2wallCollision = new StaticBodyOutOfBoundsCollisionCheck()
        ..collider1 = body2.collider
        ..collider2 = world.collider;
  
      paddle2wallCollision.onCollision.listen((event) {
        body2.position.add(event.delta);
        body2.syncToNode();
      });
  
      world.collisions.add(paddle1wallCollision);
      world.collisions.add(paddle2wallCollision);
    });
  
    game.start();
  