overlapping.dart

import 'package:flutter/material.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(
        scaffoldBackgroundColor: darkBlue,
      ),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: Stack(
            children: List.generate(13, (index) => Container(
              height: 30,
              width: 30,
              decoration: BoxDecoration(
                color: Colors.green,
                borderRadius: BorderRadius.circular(15),
              ),
            )),
          ),
        ),
      ),
    );
  }
}