// This is one implementation of the abstract class PlugInForm as defined 
//  in MyPlugIn.dll .
// Compile with the command line:
//  csc /t:library MPIPhilosopher.cs /r:MyPlugIn.dll
using System;
public class MPINihilist : PlugInForm
{
  public override void WhatIsPI()
  {
    Console.WriteLine("Who cares?");
  }
}

public class MPISolipsist
{
  public void WhatIsPI()
  {
    Console.WriteLine("PI is Mine.");
  }
}