You see twenty slides lined up like a grid. You don't know who put them here, but they almost look like the grid paper you do your maths homework in. But who would use a slide as grid paper?
As you stare at the slide grid you see some people come out and overhear them talk about their mass maths (ます) tournament happening later today. Oohhh it IS a giant grid. And they're going to use it to do maths later!