A tacit psychological game

"Green, that lunatic. He actually set us up ten years ago. He's really something!" After the two of them checked the room together and made sure that there were no bugs or cameras, Miao kun pointed at their room keys and said,"the trick is on the keys!"

"Key?" Zhao Yu checked the two keys, but didn't find anything special.

"Not these two, of course it's the key from ten years ago!" Miao kun peeked out of the window and lowered his voice."I'm sure that the clue Green Left me was a bomb!" He said to Zhao Yu carefully.

"It's a fart?" Zhao Yu was puzzled."How did you get it? Don't you find it stinky?"

"No, I said the English letter 'P'! The 'P' from the GPS! Do you understand? It's in capital!" Miao kun explained,"back when we were living on the island, green gave each of us a room key. The shape of the key and the room number behind it are the same as what we see now.

"However, the pattern on the key is different!"