Binary tree level order traversal

Program.cs

using System;
using System.Collections.Generic;

class Program
{
    class BinaryNode
    {
        public char Letter;
        public BinaryNode First = null, Second = null;
    }

    static BinaryNode BinaryTree =
    //     A
    //    / \
    //   B   C
    //  / \   \
    // D   E   F
    new BinaryNode()
    {
        Letter = 'A',

        First = new BinaryNode()
        {
            Letter = 'B',
            First = new BinaryNode() { Letter = 'D' },
            Second = new BinaryNode() { Letter = 'E' }
        },
        Second = new BinaryNode()
        {
            Letter = 'C',
            First = new BinaryNode() { Letter = 'F' }
        }
    };

    static void Main(string[] args)
    {
        Write("[ ", ConsoleColor.White);
        Write("Typical loop");
        Write(" ]\n", ConsoleColor.White);

        //Handle our own stack to prevent a StackOverflowException
        //With a typical loop it would call a method such as ProcessNode(BinaryNode), which would call itself with the nodes contained within the parent node, meaning to emulate such a process we need to use a first-in last-out collection such as Stack<T>
        Stack<BinaryNode> stack = new Stack<BinaryNode>();
        stack.Push(BinaryTree);

        BinaryNode current;
        do
        {
            current = stack.Pop();

            Write(current.Letter + " ");
            if (current.Second != null) stack.Push(current.Second);
            if (current.First != null) stack.Push(current.First); //First comes last because we're using a first-in last-out collection
        } while (stack.Count > 0);

        Write(".\n\n[ ", ConsoleColor.White);
        Write("Binary tree level order traversal");
        Write(" ]\n", ConsoleColor.White);

        //Use a queue instead of a stack for traversal, because it is first-in first-out
        Queue<BinaryNode> queue = new Queue<BinaryNode>();
        queue.Enqueue(BinaryTree);

        do
        {
            current = queue.Dequeue();

            Write(current.Letter + " ");
            if (current.First != null) queue.Enqueue(current.First); //First comes first
            if (current.Second != null) queue.Enqueue(current.Second);
        } while (queue.Count > 0);

        Write(".", ConsoleColor.White);

        Console.ReadKey();
    }

    static void Write(string str, ConsoleColor c = ConsoleColor.Gray) { Console.ForegroundColor = c; Console.Write(str); }
}