Once you know how the rating selections work, enabling the throttles to be left fully forward throughout normal flight, you can draw a line to the Airbus FBW thrust lever arrangement - the detents equating to different ratings.
Mercifully no-one had thought of that when Concorde was being designed; I still think it's a diabolical system.
BTW I was told in the conversion course that during the design phase the idea was mooted to only have one thrust lever for all four engines. This would probably have worked - even non-normal engine shutdown drills didn't require the engine's throttle to be closed, the first thing you did was pull the shutdown handle.