MaterialApp(
      home: Scaffold(
        backgroundColor: Colors.teal,
        body: SafeArea(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Container(
          height: double.infinity,
          width: 100.0,
          color: Colors.red,
        ),
            // your column widget here
        Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            // your yellow box here
            Container(
              height: 100,
              width: 100.0,
              color: Colors.yellow,
            ),
            // your green box here
             Container(
              height: 100,
              width: 100.0,
              color: Colors.green,
            ),
          ],
        ),
          Container(
          height: double.infinity,
          width: 100.0,
          color: Colors.blue,
        ),
          ],
        ),
        ),
      ), 
      debugShowCheckedModeBanner: false,     
    );