When I first visited the garden, there was a piece of ragged topiary, once carefully shaped but now left untrimmed. It stood, oddly on its own, on a patch of tired lawn. It did not seem to have been fashioned like a chess piece, or a fabulous beast, or a pyramid or a cone or a toadstool, as such carved greenery often is. It was hard indeed to make out what it was originally meant to be, but as I gazed at it I thought it looked like a key. There was a sort of oval head at the top, a thin column and then some shapes towards the base which might be the slots to fit the wards of a lock. So then I fell to thinking about a mystery which would only be solved when someone noticed this topiary and had the same idea about it. Suppose they made a sketch of the little tree, copying it quite precisely, and then had a key made in its shape. Then they searched until they found the lock that it fitted, either in a door or in a chest.