A virus is a wet nanomachine, a tiny, complicated, slightly fuzzy mechanism, which is rubbery, flexible, wobbly, and often a little bit imprecise in its operation—a microscopic nugget of squishy parts. Viruses are subtle, logical, tricky, reactive, devious, opportunistic. They are constantly evolving, their forms steadily changing as time passes. Like all kinds of life, viruses possess a relentless drive to reproduce themselves so that they can persist through time.
