Many readers will recently have watched a delightful viral video of two Italian girls, one 11 and the other 13, on the flat roofs of Liguria, playing tennis across the gap between their homes.

It’s a charming example of how people adapt to circumstances to survive — or merely to do what they wish to do. There are thousands of others: In Israel, kiosks have been built to serve as sanitary coronavirus testing booths, and road crews are mending potholes at record pace because there’s no traffic to interrupt them; in Bethesda, a restaurant wholesaler has switched to supplying retail customers who need only drive to a local school, pop the trunk of their car, and have it filled with ordered groceries; or there’s the seamstress at my dry cleaner who switched to making face masks and selling them at premium prices.