Gnomon

The beaver's tooth and the tiger's claw. Sunflowers and seashells. Fractals, Fibonacci sequences, logarithmic spirals. These diverse forms of nature and mathematics are united by a common factor: all involve self-repeating shapes, or gnomons. Almost 2000 years ago, Hero of Alexandria defined the gnomon as that form which, when added to some form, results in a new form, similar to the original. In a spiral seashell, for example, we see that each new section of growth (the gnomon) resembles its predecessor and maintains the shell's overall shape. Inspired by Hero, Midhat Gazale - a fellow native of Alexandria - explains the properties of gnomons, traces their long and colourful history in human thought, and explores the mathematical and geometrical marvels they make possible. The text should appeal to anyone interested in the wonders of geometry and mathematics, as well as to enthusiasts of mathematical puzzles and recreations.