The lesson is in the evening and something is about to go wrong beautifully. Twenty-six things hang in the air here, more than in any other world, so the candles and the lanterns on chains really do float instead of sitting on a surface. Set the desks, chalk the board, then let the room fill from the ceiling down.
Put a jar on a desk and it rides the desk. Move the desk afterwards and the cauldron, the wand and the jar of something glowing all come with it. Push the broom behind the shelves and it stays behind, so the room has a back row.
Then turn the night on. Twenty-one lights, and the floating candles are real ones: they cut small warm holes in the dark while the tall window keeps the sky. Switch one off and that corner of the classroom goes quiet.
Nothing is graded here, which is the joke, and nothing has to be handed in.
