Just managed to watch this on the computer, and there are a couple of points I would like to raise regarding Sandi's demonstration of the method of knotting a tie.
1) That is the only way I have ever knotted a tie, although the idea of having to start with the tie back to front puzzles me.
2) Regarding the alleged number of ways of tying a tie. If someone can demonstrate to me more than a dozen materially different ways of doing it I will be surprised, never mind 70,000 (or whatever fantastic number was quoted). If you are going to wear it in anything approaching a conventional manner, i.e. round your neck with two lengths hanging down in front, I can't see how there could be any significant number of variations.