Mathematical reasoning may be regarded rather schematically as the exercise of a combination of two facilities, which we may call intuition and ingenuity.
Alan TuringWhen we want to sink a convoy, we send out an observation plane first... Of course, to observe is not its real duty, we already know exactly where the convoy is. Its real duty is to be observed...Then, when we come round and sink them, the Germans will not find it suspicious.
Alan Turing