Solução do exercícios

Tentei resolver o exercicio utilizando herança dos quadrados e linhas

import 'package:flutter/material.dart';

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

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

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter: Primeiros Passos'),
        ),
        body: ListView(
          children: [
            RowQuadrados(
              cor1: Colors.cyanAccent,
              cor2: Colors.blue,
              cor3: Colors.yellow,
            ),
            RowQuadrados(
              cor1: Colors.grey,
              cor2: Colors.cyan,
              cor3: Colors.green,
            ),
            RowQuadrados(
                cor1: Colors.purple,
                cor2: Colors.lightGreenAccent,
                cor3: Colors.pinkAccent)
          ],
        ),
        floatingActionButton: FloatingActionButton(onPressed: () {}),
      ),
    );
  }
}

class RowQuadrados extends StatelessWidget {
  final Color cor1;
  final Color cor2;
  final Color cor3;

  const RowQuadrados(
      {Key? key, required this.cor1, required this.cor2, required this.cor3})
      : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(8.0),
      child: Container(
        child: Row(
          children: [
            Retangulo(cor1),
            Retangulo(cor2),
            Retangulo(cor3),
          ],
        ),
      ),
    );
  }
}

class Retangulo extends StatelessWidget {
  final Color cor;

  const Retangulo(this.cor, {Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: 100,
      height: 140,
      color: cor,
    );
  }
}