When I started my current job, I checked to see if I would have to wear a tie. I do not like ties, but I did like _The 85 Ways to Tie a Tie_ (Broadway Books) by Thomas Fink and Yong Mao. There are indeed eighty-five ways to tie a tie, and they prove it, and they show them all. If you wear a tie, or know someone who does, and especially someone who does under protest, this is a useful and entertaining little book.
But how does anyone prove that there are eighty-five ways to tie a tie? Well, the genial authors explain: "Tie knots, we realized, are equivalent to persistent random walks on a triangular lattice." If that explanation strikes you as less than useful, you can turn to the appendix at the back of the book, where you will find the random walk explanation proved by means of equations with symbols and superscripts which I cannot reproduce here. Comes the explanation: "Our day job as theoretical physicists might have had something to do with it." It does not take a mathematician to enjoy this book, however. What the authors have done is to examine all the variations of how to tie a standard tie. This means that one leaves the little end alone and makes the big end travel around to form the knot. Having crossed the little end, the big end can go to the left of it, or right, or to the center (where the neck of the wearer is). That is three possible moves, and within each of the three fields, the big end may either go in toward the wearer or out away from the wearer, for a total of six moves in all, not counting the final move, which is always to pull the big end down through the knot to its final resting place. Each knot can thus be specified with permutations of six simple moves. The simplest is the three-move variety called the "Oriental," the most complex is the nine-move memory-breaker known as the "Balthus." Windsor, half-Windsor, four-in-hand, and all the others are shown and instructions given. The authors have also noted the methods which might help make a more impressive knot in a lightweight tie, or in a tie that has grown limp with use, and various other suggestions. There is art here as well as science.
This is a unique blend of mathematics, sartorial history, and fashion instruction, wittily presented and attractively illustrated. If we have to have ties, we might as well let them teach us something.