Thread by @skarlamangla

I just realized that an Indian folktale my dad told me when I was a kid prepared me to cover COVID and my mind is blown. so this is how it goes:

(stay tuned if you want to understand how COVID outbreaks seem to suddenly become unstoppable!)

an Indian king made all of his subjects give him the rice they grew every year and didn't leave them any of the surplus. then there was a famine and the villagers had no rice and the king wouldn't give them any because he wanted to save it for himself

a smart little girl convinced the king to give her just one grain of rice today and then for the next thirty days, double the rice he had given her the day before. so tomorrow, he'd give her two grains, the next day four grains, and so on for thirty days

on the ninth day, the king gave the little girl 256 grains of rice. so far, she'd gotten 511 grains total, just about enough only a small handful. the king starts to think that the girl isn't very smart since he's barely given her any rice

on the 13th day, she got 4,096 grains, enough to fill a small bowl. on the 16th, she got 32,768 grains. all together, the little girl had gotten enough rice to fill up two bags which, while a good amount, barely made a dent in the king's stockpile so he remained unfazed

but then on the 24th day, the king had to give her 8,388,608 grains of rice. on the 29th, the girl was presented with the contents of two royal rice storehouses. and on the 30th day, the king had to give her 536,870,912 grains of rice, clearing out the final four storehouses

in total, the girl received more than a billion grains of rice in 30 days!

obviously I loved this story as a kid because it was about a little girl outsmarting a king, but now I've realized it's literally just a story about exponential growth and how it surprises everyone

if we think about each grain of rice as a person, the first one is a person with COVID, who then gives it to two other people

those two people then give it to two more, and those next four people each give it to two people, so they infect eight people etc etc

by just the sixth infection cycle, 127 people have COVID -- first 1, then 2 more, then 4 more, then 8 more, then 16 more, then 32 more, then 64 more. this is why it seems like small numbers suddenly turn into thousands.

by day 10, we've totaled more than 1,000 grains of rice

and that's what happens if people *don't* change their behavior and each sick person just keeps infecting two people throughout. if we drop our guard etc, they might infect even more and the numbers could clim even faster

anyway, I'm thinking that instead of writing this big story we should've just posted a link to this folktale latimes.com/california/sto…

here is a link to the folktale jwilson.coe.uga.edu/EMT668/EMAT668…