simple flutter gist for https://dartpad.dartlang.org/embed-flutter.html?id=53b50ef06f99b97207b8f9434b60bdcf

main.dart

import 'package:flutter/material.dart';

class ExampleScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Hey there, boo!'),
      ),
      body: Padding(
        padding: EdgeInsets.all(8.0),
        child: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: [
              Text('You are pretty okay.'),
              Text('Let\'s play'),
            ],
          ),
        ),
      ),
    );
  }
}

void main() {
  runApp(
    MaterialApp(
      debugShowCheckedModeBanner: false,
      home: ExampleScreen(),
    ),
  );
}