feat(sanbox): including Flipper example

packages/pinball_components/sandbox/lib/main.dart

@@ -15,5 +15,6 @@ void main() {
   addBallStories(dashbook);
   addLayerStories(dashbook);
   addEffectsStories(dashbook);
+  addFlipperStories(dashbook);
   runApp(dashbook);
 }

packages/pinball_components/sandbox/lib/stories/flipper/basic.dart

@@ -0,0 +1,26 @@
+import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:pinball_components/pinball_components.dart';
+import 'package:sandbox/common/common.dart';
+
+class BasicFlipperGame extends BasicGame {
+  static const info = '''
+      Basic example of how a Flipper works.
+''';
+
+  @override
+  Future<void> onLoad() async {
+    await super.onLoad();
+
+    final center = screenToWorld(camera.viewport.canvasSize! / 2);
+
+    final leftFlipper = Flipper(side: BoardSide.left)
+      ..initialPosition = center - Vector2(Flipper.size.x, 0);
+    final rightFlipper = Flipper(side: BoardSide.right)
+      ..initialPosition = center + Vector2(Flipper.size.x, 0);
+
+    await addAll([
+      leftFlipper,
+      rightFlipper,
+    ]);
+  }
+}

packages/pinball_components/sandbox/lib/stories/flipper/flipper.dart

@@ -0,0 +1,15 @@
+import 'package:dashbook/dashbook.dart';
+import 'package:flame/game.dart';
+import 'package:sandbox/common/common.dart';
+import 'package:sandbox/stories/flipper/basic.dart';
+
+void addFlipperStories(Dashbook dashbook) {
+  dashbook.storiesOf('Flipper').add(
+        'Basic',
+        (context) => GameWidget(
+          game: BasicFlipperGame(),
+        ),
+        codeLink: buildSourceLink('ball/basic.dart'),
+        info: BasicFlipperGame.info,
+      );
+}

packages/pinball_components/sandbox/lib/stories/stories.dart

@@ -1,2 +1,3 @@
 export 'ball/ball.dart';
+export 'flipper/flipper.dart';
 export 'layer/layer.dart';