using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        byte[] a = new byte[] { 223, 13, 32, 121, 151, 1 };

        byte[] b = new byte[] { 223, 12, 32, 121, 111, 1 };

        var bobHatesVar = GetDifferenceIndexes(a, b);

        //get an enumeration of index

        Console.WriteLine(bobHatesVar);

    }

    private static IEnumerable<int> GetDifferenceIndexes(byte[] a, byte[] b) 

    {

        //this method should return an enumerations of positions in the byte arrays that differ

        //between the two arrays.  For our example above, it should return [1,4].

        //if there are no differences, return an empty enumerable - not null

        throw new NotImplementedException("ah!");

    }

}