In "Ball Lightning", Lin Yun and I said that the angel on the tip of the needle means that the protagonist is doing meaningless research.

The angel on the tip of the needle is a philosophical debate in Western scholastic religion. In order to promote the power of God, it was said that angels are everywhere listening to human voices, so there are many angels wandering around, so even if a needle falls It would hit an angel. Later, I said that angels can be big or small, so small that you can stand on the tip of a needle. The specific number is 36,000, or 3,600. There is no limit to the specific description, and it is a waste of brain cells.