"What's up?"
"Take a look at this!" Yang Chuxia handed a piece of paper to Ye Zi'an. "Can you tell what this is?"
"A box!"
Yang Chuxia glared at him, "Of course it's a box, but look here!"
"Are these words engraved on it?" It wasn't Ye Zi'an's fault that he couldn't understand; he hadn't seen any modern stuff, let alone Arabic numerals.
"Let me tell you, this is a password, kind of like the mechanisms we talk about today," said Yang Chuxia. "This is a password-protected box that you can set your own password for, and no one else can open it unless they know the password."
"Really? I bet wealthy families would love this kind of box, whether it's the male or female head of the household," Ye Zi'an laughed. "But to make it, you can't use ordinary wood. It should be made of particularly hard wood, like the ceylon ironwood from the south, or made of iron. But both of these materials are expensive."