The teacher in the classroom asked four students, how can you fill the entire room?

The first one brought straw to cover the floor, the teacher shook his head.

The second one took a candle to light it, the room was filled with light, but the teacher still shook his head, because the shadows were not illuminated.

The third one took out an induction cooker and hot pot base to cook hot pot, the aroma filled the room, the teacher was somewhat satisfied but still shook his head.

The fourth student took out a warehouse full of BTC, and the anxiety of missing out instantly filled the entire school…....