钟表匠的最后一把钥匙

An old clockmaker promised to give his shop to the student who could unlock a small iron box. Three students tried every key in the shop, but none worked. The youngest student, Ada, noticed that the box had no keyhole at all.

Instead of searching for another key, Ada listened to the box. She heard a quiet ticking sound and turned it around. On the bottom were the words WAIT FOR MIDNIGHT. At twelve, the lid opened by itself. Inside was not a key but a message: “A good clockmaker understands time before tools.” Ada had solved the test by noticing what the others expected to find. The old man smiled and chose Ada to take care of the shop.