The double diffuser, the blown diffuser, the f-duct, the w-duct and the exhaust ducting diffuser are all demonstrations of the increasing complexity in Formula One aerodynamics.
Back in the era of rubber skirts and ground effect, aerodynamics was well understood but development techniques were far less precise, with many designs tried out in very basic wind tunnels or simply mocked up on the full-size car and tested for the first time out on track.
Wind tunnels with rolling roads became increasingly more available in the 1980s but even into the mid 1990s many teams were still only running in 1/3-scale or 40-percent tunnels.
The complexity of designs that could be developed and tested were limited by the size of the models and the manufacturing techniques, with most wind tunnel model parts made painstakingly by hand by model makers whose tools were chisels and sand paper.
Their skill was to craft precise shapes in wooden moulds that would then be used to create accurate carbon fibre parts for testing but despite impressive craftsmanship the opportunity to explore complicated shapes was severely restricted.
Even by then, wind tunnel testing was no longer about using the limited time to throw on radical concepts seeking big step-change improvements. It was now about maximising a consistently scheduled rotation of testing with iterative development that chased hundredths and tenths of a second and top team wind tunnels, as they do now, were running 24-7.
Since then, however, tunnels have got bigger and two major advancements in technology have changed the way things work, making innovation key again: CFD and rapid prototyping.
And the difference they have made is in increasing complexity.
The first element, CFD, may not be good enough to replace wind tunnel testing yet — as demonstrated by Virgin's decision to ditch their all-CFD approach and bring back more traditional techniques - but it does allow teams to visualise flows like never before and understand where the air - in theory at least — is travelling across and through the parts they create.
Without this, the complex channels that steer exhaust gases down to diffusers, the detailed brake duct designs or the innovative flow regimes used on the f-duct and w-duct, would have been too time consuming and risky to gamble on and would not have been explored.
But CFD is still not always right, which is where rapid prototyping helps turn these complex approaches into reality.
Now, designers can create complex shapes on computer design programmes and send the file directly to a rapid prototyping machine, which will turn that 3D drawing into a tangible part created from a big pool of liquid resin using a laser that solidifies it layer by layer, less than a millimetre at a time.
Watching one of these machines in creation is incredible — but what's more incredible is how it's changed the opportunity for development.
The latest concept of 'fluidic switches' - which take air from one part of the car and feed it through to another to alter the behaviour of the flow in that area — is a case in point.
Although the w-duct will be banned from next year, the general concept has been installed in engineers' minds and the facility to develop at this level has been realised.
For example, there are suggestions that Ferrari have already tried a system to alter the downforce on different sides of their front wing in cornering, and there are plenty more ideas where that came from.
Now engineers have the tools to develop in detail, they can think in even more complex ways. And that will make the FIA's policing job harder than ever.
- Formula One