Flutter: Widgets, Containers e desenho de tela

import 'package:flutter/material.dart';
/**
 * Dev: Rafael Costa
 */
void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.red,
      ),
      home: Container(
        color: Colors.black,
        child: Column(
            mainAxisAlignment: MainAxisAlignment.spaceAround,
            children: [
              Row( mainAxisAlignment: MainAxisAlignment.spaceAround, 
              children: [
                        Container(color: Colors.red[600], height: 120, width: 120,), 
                        Container(color: Colors.orange[600], height: 120, width: 120,),  
                        Container(color: Colors.yellow[600], height: 120, width: 120,),
              ]   
              ),
              Row( mainAxisAlignment: MainAxisAlignment.spaceAround, 
              children: [
                        Container(color: Colors.green[600], height: 120, width: 120,), 
                        Container(color: Colors.cyan[400], height: 120, width: 120,),  
                        Container(color: Colors.blue[600], height: 120, width: 120,), 
              ]  
              ),
                            Row( mainAxisAlignment: MainAxisAlignment.spaceAround, 
              children: [
                        Container(color: Colors.purple[600], height: 120, width: 120,), 
                        Container(color: Color.fromRGBO(233, 30, 99, 1) , height: 120, width: 120,),  
                        Container(color: Colors.white, height: 120, width: 120,),  
              ]
              ),
            ]),
      ),
    );
  }
}