ABSTRACT
ART. 11.1. INTRODUCTION P e r h a p s one of the most beautiful structural shapes in nature is the shell of an egg, combining, as it does, extreme fitness for its purpose with an economy of material and a cleanliness of design which is the envy of engineers and architects. Yet as far as we know the hen manages to construct her shells without a knowledge of mathematics involving double integrals and Fourier series. Consider also an ordinary drinking-straw, manufactured by form ing quite thin paper into a tube about 9 in. long x ^ in* diameter: this tube will certainly carry its own weight over a span equal to its own length; but if the same tube is unrolled and the paper laid flat, it will sag and collapse on only a fraction of the span. These simple examples show what can be achieved when the engineer is given control of his shapes.
