Short version: I said they couldn’t stick pencils in the ceiling tiles.

BTW this all was done with friction. I’m curious to see what remains in the morning.

Longer version: One of my English composition students wanted to toss and stick a pencil into a ceiling tile. No, I said, it’ll be a hazard when it falls. He complied but then remembered this trick and went and rubbed a pencil onto the wall, which I was fine with. His buddy had to try it too, and then most of the class got involved and used every spare pencil they could find. It was science, it was bonding and it took maybe five whole minutes, a win all around. After school I instructed the custodian to leave the pencils alone, including any that dropped, so we could track the progress.