“Mean?” said Anthony. “There’s only one thing it can mean. The late Count Stylptitch must have had a sense of humour! This is an example of that humour. I may say that I don’t consider it particularly funny myself.”

“Do you mind explaining your meaning a little more clearly, sir?” said Superintendent Battle.

“Certainly. This was the Count’s little joke. He must have suspected that his memorandum had been read. When the crooks came to recover the jewel, they were to find instead this extremely clever conundrum. It’s the sort of thing you pin on to yourself at book teas, when people have to guess what you are.”

“It has a meaning, then?”

“I should say, undoubtedly. If the Count had meant to be merely offensive, he would have put a placard with ‘Sold’ on it, or a picture of a donkey or something crude like that.”