When a crossword clue won’t give, it is rarely because you don’t know the answer. More often you decided, before you noticed deciding, what kind of word the clue was. In cryptic puzzles “flower” is as likely to be a river as a rose, because a river is a thing that flows, and “number” can be an anaesthetic, a thing that numbs. The setter hid nothing. Every letter was in plain sight; you gave it the wrong sound in your head and then searched very hard inside that sound. That is why the answer so often turns up the next morning, or the moment you put the pen down to make tea. You didn’t learn anything overnight. You only forgot, for a second, how you had chosen to read it, and the other reading was there the whole time, spelled exactly the same.