gistfile1.cs

using System;

class Base
{
    private string x = "x".Print();
}

class Derived : Base
{
    private string y = "y".Print();
    private string z;

    public Derived()
    {
        this.z = "z".Print();
    }
}

static class Program
{
    static void Main()
    {
        new Derived(); // y x z
    }

    public static string Print(this string s)
    {
        Console.WriteLine(s);
        return s;
    }
}