sa25-timeline2.dart

var _tween = TimelineTween<AniProps>()
  ..addScene(begin: 0.seconds, duration: 1.seconds)
      .animate(AniProps.x, tween: (-100.0).tweenTo(100.0)) // x to right
  ..addScene(begin: 1.seconds, duration: 1.seconds)
      .animate(AniProps.y, tween: (-100.0).tweenTo(100.0)) // y down
  ..addScene(begin: 2.seconds, duration: 1.seconds)
      .animate(AniProps.x, tween: (100.0).tweenTo(-100.0)) // x to left
  ..addScene(begin: 3.seconds, duration: 1.seconds)
      .animate(AniProps.y, tween: (100.0).tweenTo(-100.0)); // y up