using System;

​

public class Program

{

    public static void Main()

    {

        Foo one = new Foo();

        Foo two = new Foo();

        Console.WriteLine("Foo one AND Foo two");

        bool a = one.Equals(two);

        bool b = one == two;

        Console.WriteLine("Foo one AND object three (which is still Foo)");

        object three = two;

        bool c = one.Equals(three);

        bool d = one == three;

        Console.WriteLine("object three (which is still Foo) AND Foo two");

        bool e = three.Equals(one);

        bool f = three == one;

    }

}

​

class Foo

{

    public override bool Equals(object that){

        Console.WriteLine("Custom Equals");

        return base.Equals(that);

    }

    public static bool operator == (Foo lhs, Foo rhs) {

        Console.WriteLine("Custom ==");

        return object.ReferenceEquals(lhs, rhs);

    }

    public static bool operator != (Foo lhs, Foo rhs) {

        Console.WriteLine("Custom !=");

        return !object.ReferenceEquals(lhs, rhs);

    }

}