For the current season Formula 1 introduced the most radical change in aerodynamics regulations since 2009.
That has had the effect of shaking up the established pecking order, but why were the new rules brought in and why have some teams struggled to come to terms with them? We take a look.
Fans and casual observers of F1 have long bemoaned the fact that overtaking has become a rarity in the sport, even when the car behind is clearly much faster than the one it is trying to overtake.
That was because the aerodynamic appendages of the car behind couldn't work as efficiently when running in the disturbed air being left behind by the car ahead.
Air behaves like a liquid, and a simple analogy is that driving in clear air is like swimming on your own in a swimming pool, while driving in the wake of a car ahead is like swimming in the sea, against the tide.
So rule-makers wanted to change the way the cars generate the grip that allows them to take corners at mind-blowing speed, in a way that reduced the severity and the effect of the wake from following a car, so that a driver trying to overtake another competitor could follow much closer without losing grip, and therefore have a better chance to overtake.
Anyone who watched the five-car midfield battle in Austria last weekend will be left in no doubt that the changes have worked, and while overtaking has still proved difficult at some circuits, in general the changes have been a great success.
This has been achieved by looking back to a technology pioneered in the late 1970s, known as ground effect. It involves shaping the floor of the car in such a way as to create a vacuum beneath it which literally sucks the car to the road.
Ground effect was banned in 1983 due to safety concerns. If the vacuum was broken in mid-corner because of reliability issues or a collision, the car would suddenly lose massive amounts of grip and fly off the road at high speed.
Since then, aerodynamic grip has been generated by air flowing over the top of the car, which creates much more wake. But it was felt that car and circuit safety has moved on enough since the early 80s to bring back ground effect.
Generally speaking, teams begin a new season with an evolution of the previous year's car. That gives an inherent advantage to the teams at the head of the field last year, and is partly responsible for Mercedes putting together an unprecedented run of eight consecutive constructors' championships.
However, with such sweeping changes, all the teams start from a blank slate, and while those with the most money and best resources will still have an advantage, there is a greater chance of a shake-up in the order.
It is perhaps not a surprise that Red Bull have jumped to the top of the order. Their technical director, Adrian Newey, is the only person in his role in the paddock who was around when ground effect was last used in F1.
Quite apart from that, he designed dominant cars for Williams in the mid-1990s, McLaren later that decade and Red Bull in the 2010s.
Many cars suffered with 'porpoising' on the straights earlier in the season - a violent bouncing at high speed caused by the vacuum beneath the car being broken when the floor hits the ground, and then reforming.
Mercedes suffered particularly badly with that, but seem to have got it under control now, while the Williams car was noticeably bouncing down the straights in Austria.
Chequered Flag - Austrian GP Review
Chequered Flag - British GP Review
Chequered Flag - Canada GP Review
Cars are chiefly designed using the help of computational fluid dynamics (CFD) - a kind of computer-simulated wind tunnel. The problem is that, like all computer programs, it can only simulate the conditions that it is told to, while in the real world, different conditions will inevitably crop up.
Teams use pre-season testing and pre-race practice sessions to compare how their car behaves in real-world environments with what the CFD suggested, and in some cases there is quite a difference.
With cars generating their grip in a very different way to what they have used for the last 40 years, it's no wonder some teams are struggling, as some will have got a lot of their calculations wrong.
Mercedes engineer Andrew Shovlin explained that solving this year's car has been like peeling an onion - once one layer of problems has been fixed it just reveals another layer previously hidden.
Not that it has been a disastrous year for Mercedes. They have seven podiums from 11 races and sit a strong third in the constructors' standings.
There is still a lot to fix on the Mercedes, which is cumbersome in slow corners and struggled for top-speed in Austria, but if they are able to finish peeling the onion before the end of the year, then Lewis Hamilton could still have a real chance of extending his record of winning a race every year of his career.
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