For the better part of a century, most biologists have been reluctant to use those words, mindful of a principle of evolution that says "evolution cannot run backwards".
Last season, however, Lennon seemed to take an unsteady step backwards at White Hart Lane, while Walcott made a rocket-assisted international take-off on a memorable night in Zagreb.
The problem is that because of their focus in design strategy and management they do tend to get rusty, in fact very rusty with the technical design stuff.