Oklahoma City, December, 1917. Emerson High School's custodian, R. J. Scott, has taken delivery of brand-new slate blackboards to replace the old ones that are not in good condition. He writes on each room's old board that today is the day the new ones are going to be installed.
It's a pretty big deal.
But R.J. got lazy, faced with several rooms to work on over a week's time; and he decided to just mount the new boards right over the old boards.
And two days ago workers came to remove the chalkboards altogether; they're installing network cables in this building that was built in 1895 and has been the High School since then.
And when they removed the first layer of slate, they found those old blackboards from 1917, with the lessons still on them.
Over the years we teach kids how to do math in radically different ways. But here's your challenge: WTF is this? How does it work?
WaPo story