[Sugestão] [Duvida] resolução do exercício

ome: Column( mainAxisAlignment: MainAxisAlignment.spaceEvenly, crossAxisAlignment: CrossAxisAlignment.center, children: [ Row( mainAxisAlignment: MainAxisAlignment.spaceEvenly,

          children: [
            Container(color: Colors.red, height: 100, width: 100,),
            Container(color: Colors.orange, height: 100, width: 100,),
            Container(color: Colors.yellow, height: 100, width: 100,),
          ],
        ),
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: [
            Container(color: Colors.green, height: 100, width: 100,),
            Container(color: Colors.cyan, height: 100, width: 100,),
            Container(color: Colors.blue, height: 100, width: 100,),
          ],
        ),
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: [
            Container(color: Colors.purple, height: 100, width: 100,),
            Container(color: Colors.pink, height: 100, width: 100,),
            Container(color: Colors.white, height: 100, width: 100,),
          ],
        )
      ],
    )
);

} }

Tenho apenas uma duvida na questão do crossAligment, não entendi muito bem como ele funciona.