FluentInterfaceHierarchy

using System;
using System.Collections.Generic;
using System.Threading;

namespace DesignPatterns
{
  public class Person
  {
    public string Name;

    public string Position;

    public DateTime DateOfBirth;
    
    public class Builder : PersonBirthDateBuilder<Builder>
    {
      internal Builder() {}
    }
    
    public static Builder New => new Builder();

    public override string ToString()
    {
      return $"{nameof(Name)}: {Name}, {nameof(Position)}: {Position}";
    }
  }

  public abstract class PersonBuilder
  {
    protected Person person = new Person();

    public Person Build()
    {
      return person;
    }
  }

  public class PersonInfoBuilder<SELF> : PersonBuilder
    where SELF : PersonInfoBuilder<SELF>
  {
    public SELF Called(string name)
    {
      person.Name = name;
      return (SELF) this;
    }
  }

  public class PersonJobBuilder<SELF> 
    : PersonInfoBuilder<PersonJobBuilder<SELF>>
    where SELF : PersonJobBuilder<SELF>
  {
    public SELF WorksAsA(string position)
    {
      person.Position = position;
      return (SELF) this;
    }
  }

  // here's another inheritance level
  // note there's no PersonInfoBuilder<PersonJobBuilder<PersonBirthDateBuilder<SELF>>>!

  public class PersonBirthDateBuilder<SELF> 
    : PersonJobBuilder<PersonBirthDateBuilder<SELF>>
    where SELF : PersonBirthDateBuilder<SELF>
  {
    public SELF Born(DateTime dateOfBirth)
    {
      person.DateOfBirth = dateOfBirth;
      return (SELF)this;
    }
  }

  internal class Program
  {
    class SomeBuilder : PersonBirthDateBuilder<SomeBuilder>
    {

    }

    public static void Main(string[] args)
    {
      var me = Person.New
        .Called("Dmitri")
        .WorksAsA("Quant")
        .Born(DateTime.UtcNow)
        .Build();
      Console.WriteLine(me);
    }
  }
}