[Dúvida] o retorno do Widget

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          leading: const Icon(Icons.add_task),
          backgroundColor: Colors.blue,
          title: const Text(
            'Flutter: Projeto Cores',
            style: TextStyle(color: Colors.white),
          ),
        ),
        body: const ColorsBox(),
      ),
    );
  }
}

class ColorsBox extends StatefulWidget {
  const ColorsBox({super.key});

  @override
  State<ColorsBox> createState() => _ColorsBoxState();
}

class _ColorsBoxState extends State<ColorsBox> {
  int colornum = 0;

  List<Widget> colorSet = [
    createColor(Colors.blue, Colors.blue, Colors.blue),
    createColor(Colors.green, Colors.blue, Colors.purple),
    createColor(Colors.orange, Colors.red, Colors.grey),
    createColor(Colors.black, Colors.yellow, Colors.brown),
    createColor(Colors.green.shade50, Colors.deepOrange, Colors.blue.shade700),
  ];
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(8.0),
      child: Column(
        children: [
          colorSet[colornum % colorSet.length],
          colorSet[colornum % colorSet.length],
          colorSet[colornum % colorSet.length],
          ElevatedButton(
            style: ButtonStyle(
              fixedSize: const MaterialStatePropertyAll(Size(100, 30)),
              backgroundColor: MaterialStatePropertyAll(Colors.green.shade500),
            ),
            onPressed: () {
              setState(
                () {
                  colornum++;
                },
              );
            },
            child: const Icon(Icons.check),
          ),
        ],
      ),
    );
  }
}

Widget createColor(Color color1, Color color2, Color color3) {
  return Padding(
    padding: const EdgeInsets.all(8.0),
    child: Row(
      children: [
        Container(
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(20),
            color: color1,
            border: Border.all(color: Colors.black, width: 2),
          ),
          width: 80,
          height: 110,
        ),
        Container(
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(20),
            color: color2,
            border: Border.all(color: Colors.black, width: 2),
          ),
          width: 80,
          height: 110,
          child: const Icon(Icons.person),
        ),
        Container(
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(20),
            color: color3,
            border: Border.all(color: Colors.black, width: 2),
          ),
          width: 80,
          height: 110,
        ),
      ],
    ),
  );
}