A driven nail holds two pieces of wood together not by bonding to them but by the compressive friction of displaced fibres gripping its shaft along its length. This is why pulling a nail straight out is hard while the same force applied as leverage extracts it easily: the hold depends on sustained lateral pressure, not on any adhesive contact.
The nail, wheel, spring, magnet, lens, string and pump are each thousands of years old yet remain irreducible building blocks inside today's most advanced technology, from smartphones to spacecraft. Complexity is not built from novel primitives but from endlessly recombining and miniaturising these same few old mechanisms.
Looking at a built object through its smallest functional components, rather than its overall purpose, reveals that a phone camera is a lens and a spring, a hard drive is a magnet, and a crane is a string under tension. The impressive whole is demystified once you trace which ancient element is doing each job.
Roma Agrawal recounts that her great-grandfather worked on extracting metals and that her own family history is bound up with pumps moving fluids, framing the pump chapter through this personal lineage. She uses the body's own pump, the heart, and the invention of mechanical and later implantable pumps to show how moving liquids reliably is foundational to both industry and keeping people alive.