The stripes of a zebra...the complexities of a spider's web...the waves of the ocean...and the shape of a snowflake. These and other natural patterns have been recognized by scientists for centuries. What do they have in common? They can all be accounted for mathematically. In What Shape is a Snowflake? internationally acclaimed mathematician Ian Stewart shows how life on earth develops not simply from genetic processes, but also from the principles of mathematics. Starting with the simplest symmetrical patterns, each chapter looks at a different kind of patterning system and the key scientific issues that underlie it. Patterns can embrace chaos, fractals, dislocations, even statistical regularities, and are found in many things that at first seem irregular or featurless. A constant wind blowing over a flat expanse of sand, for example will develop ripples, which eventually lead to sand dunes that are often arranged in long parallel rows or other geometric forms. And the smooth surface of a growing organism will develop beautiful patterns, of spots, stripes and colors. Beautifully illustrated, What Shape is a Snowflake? is an illuminating and engaging vision of how the apparently cold laws of mathematics find organic expression in the beauty of nature.