The use of knots may predate mode humans (Homo sapiens). For example, seashells colored with ocher, pierced with holes, and dated to 82,000 years ago have been discovered in a Moroccan cave. Other archeological evidence suggests much older bead use in humans. The piercing implies the use of cords and the use of a knot to hold the objects to a loop, such as a necklace. The quintessence of oamental knots is exemplified by The Book of Kells, an oately illustrated Gospel Bible, produced by Celtic monks in about A.D. 800. In mode times, the study of knots, such as the trefoil knot with three crossings, is part of a vast branch of mathematics dealing with closed twisted loops. In 1914, German mathematician Max Dehn (1878-1952) showed that the trefoil knot's mirror images are not equivalent. For centuries, mathematicians have tried to develop ways to distinguish tangles that look like knots (called unknots) from true knots and to distinguish true knots from one another. Over the years, mathematicians have created seemingly endless tables of distinct knots. So far, more than 1.7 million nonequivalent knots with pictures containing 16 or fewer crossings have been identified. Entire conferences are devoted to knots today. Scientists study knots in fields ranging from molecular genetics-to help us understand how to unravel a loop of DNA-to particle physics, in an attempt to represent the fundamental nature of elementary particles. Knots have been crucial to the development of ci

October 17, 1946D'Arline,I adore you, sweetheart.I know how much you like to hear that — but I don't only write it because you like it — I write it because it makes me warm all over inside to write it to you.It is such a terribly long time since I last wrote to you — almost two years but I know you'll excuse me because you understand how I am, stubbo and realistic; and I thought there was no sense to writing.But now I know my darling wife that it is right to do what I have delayed in doing, and that I have done so much in the past. I want to tell you I love you. I want to love you. I always will love you.I find it hard to understand in my mind what it means to love you after you are dead — but I stil] want to comfort and take care of you — and I want you to love me and care for me. I want to have problems to discuss with you — I want to do little projects with you. I never thought until just now that we can do that. What should we do. We started to lea to make clothes together — or lea Chinese — or getting a movie projector. Can't I do something now? No. I am alone without you and you were the "idea-woman" and general instigator of all our wild adventures.When you were sick you worried because you could not give me something that you wanted to and thought I needed. You needn't have worried. Just as I told you then there was no real need because I loved you in so many ways so much. And now it is clearly even more true — you can give me nothing now yet I love you so that