Analogue Computers
Vincent Walsh · 1985
If you are sitting on a chair as you read this book, then your body is exerting a pressure on the chair which can vary from one microsecond to another, according to how much you shift around, how you sit in the chair, and so on. At the same time, your heart is pumping blood through your arteries and veins but the rate of flow of that blood is not constant: it ebbs and flows in rhythm with the beating of your heart. The movements of your eyes, as you read these words, are shifting and changing continuously.