Petzold’s style of writing while maintaining a scientific yet conversational tone, makes his coverage of morse code, simple circuits , Braille and eventually the Indo-Arabic decimal system a pleasure to read. While I am familiar with some of the concepts that are covered, his approach to teaching the reader about to subject matter is refreshing and insightful. As a sighted person, I had given little thought to braille or what a shift code could mean. This concept of a context driven code is interesting and more complex than I initially thought. My first impulse was to consider Braille as a textured morse code, fixed in meaning. Since there is a duplication of meanings for some of the letters, there is a complexity that renders braille as a code that feels a bit like a language. This is not to say that Braille has the full qualities of a separate language, however, it is not a simple code that can be mindlessly reproduced like the morse code via use of a repeater. Braille requires a thinking mind or a sufficiently advanced algorithm to recognize the grammatical context of the word.

Aside from Braille, the second most fascinating port of the reading was the way that Petzold skillfully unraveled the decimal system. After being so far removed form my mathematics classed from my childhood, it was refreshing to recount these simple mathematical truths about the numbers that surround my daily life. I recall thinking to myself that as children, we initially study math so that we can use it practically. Mathematical expansion was an exercise such that we would understand the basic principles, and then later forget some of the beautiful simplicity of our number system. Petzfold recaptures that childhood joy of counting and expanding large numbers.