The Washington Post: Why outbreaks like coronavirus spread exponentially, and how to “flatten the curve”. (Free access.)

“[It] is instructive to simulate the spread of a fake disease through a population. We will call our fake disease simulitis. […]

Simulitis is not covid-19, and these simulations vastly oversimplify the complexity of real life. Yet just as simulitis spread through the networks of bouncing balls on your screen, covid-19 is spreading through our human networks – through our countries, our towns our workplaces, our families. And, like a ball bouncing across the screen, a single person’s behavior can cause ripple effects that touch faraway people.

In one crucial respect, though, these simulations are nothing like reality: Unlike simulitis, covid-19 can kill. Though the fatality rate is not precisely known, it is clear that the elderly members of our community are most at risk of dying from covid-19.”