Here is a another lesson on exponential growth and a warning to states who are lulled into complacency with their relative low case rates.

Beyond the bad coronavirus numbers lie the good ones.
They’re every bit as powerful.

A math teacher once shared the parable of the clever peasant girl and the single grain of rice. The child asked the king to give her a speck of rice as a reward for a good deed, and to double the reward each day for a month. At the end of a week, the girl looked quite foolish, for she had barely a few mouthfuls of rice, despite the favor of the king.

She was hungry, but patient. Her exponential engine kept chugging away, rice to the second power, as 64 grains became 128, and 256, and 512. By the 11th day, one grain of rice had become more than 1,000. On the last day of the month, a cavalry of royal elephants was needed to carry a mountain of rice to the girl.

I think of that lesson each morning when I log on to my computer or click the TV remote. The world is filling with covid-19 patients like grains of feverish rice. When March began, there weren’t 20,000 known patients in the whole world beyond China. This morning, I learned that 20,000 new cases were identified in the past day in the United States alone.

Most of us hear about the girl with a single grain of rice clutched in her palm and we react like the king. “It’s going to be just fine,” said the king — er, the president — when the United States’ first covid-19 case presented in January. And a few days later: “We have very little problem in this country.” And March 5 on Twitter: “Only 129 cases.”

But some people learn of the deal struck by the peasant girl and immediately flash forward to the inevitable phalanx of rice-toting elephants. For them, the single grain foretells the mountain; they have the makings of epidemiologists. They are the Anthony Faucis and the Deborah Birxes, the A students in the front row of the administration whose mathematical insights are worth listening to because they are relentlessly correct, no matter what the spitballers in the back of the room might say…

…This math will give us a vaccine or cure, as sure as the doubling of those rice grains. The solution is coming — though not by the end of April or even Labor Day. We the people are the bridge from bad math to good. If we stay strong now, when the arithmetic is so fearsomely hostile, we’ll be rewarded as the calculus swings in our favor. As surely it will, because numbers don’t lie. — David Von Drehle, Washington Post