Reposted Masks https://t.co/eD8TjYbNs2 https://t.co/7Ezbi4ttn1 pic.twitter.com/L77HiJ2Qw6— XKCD Comic (@xkcdComic) October 2, 2020 Mask effectiveness scale https://twitter.com/xkcdComic/status/1312094286515593216
