static void Main(string[] args)
{
Visitor v1 = new ConcreteVisitor1();
Visitor v2 = new ConcreteVisitor2();
Element e1 = new ConcreteElementA();
Element e2 = new ConcreteElementB();
e1.Accept(v1);
e2.Accept(v1);
Console.WriteLine("————————————");
e1.Accept(v2);
e2.Accept(v2);
Console.ReadLine();
}