'see the world in a pendulum's swing'

Galileo conceded that the study of pendulums “may appear to many exceedingly arid,” although it was anything but that, as later work showed. In mathematics, pendulums stimulated the development of calculus through the riddles they posed. In physics and engineering, pendulums became paradigms of oscillation. Like the line in William Blake’s poem about seeing the world in a grain of sand, physicists and engineers learned to see the world in a pendulum’s swing. The same mathematics applied wherever oscillations occurred. The worrisome movements of a footbridge, the bouncing of a car with mushy shock absorbers, the thumping of a washing machine with an unbalanced load, the fluttering of venetian blinds in a gentle breeze, the rumbling of the earth in the aftershock of an earthquake, the sixty-cycle hum of fluorescent lights—every field of science and technology today has its own version of to-and-fro motion, of rhythmic return. The pendulum is the granddaddy of them all. Its patterns are universal. Arid is not the right word for them.

—Steven Strogatz, Infinite Powers (2019)