using System;

​

public class MainClass{

    public int firstVar = 42;

}

​

public class ZoomInAssignment {

    public MainClass mainClass;

    public void setFirstVar(){

        mainClass.firstVar = 10;

    }

}

​

public class PatioToggle {

​

    public MainClass mainClass;

    public void printThis(){

        Console.WriteLine(" mainClass.firstVar should be 10: " + mainClass.firstVar);

    }

}

​

public class Program

{

    public static void Main()

    {

        MainClass mc = new MainClass();

        ZoomInAssignment za = new ZoomInAssignment();

        PatioToggle pt = new PatioToggle();

        za.mainClass = mc;

        pt.mainClass = mc;

        za.setFirstVar();

        pt.printThis();

        //Console.WriteLine("Hello World");

    }

}