The 2014 season brought with it one of the biggest technical revolutions Formula One has ever seen.
The old, reliable V8 engines were out, replaced by cutting-edge V6 turbo hybrids. The new engines—or "power units," as they were known—were brought in to keep the manufacturers happy and to push F1 into a new era of efficient, cleaner racing.
It should have been the start of a beautiful new era for the sport—but not everyone got it right.
Mercedes dominated the season, winning 16 of the 19 races. The Silver Arrows were never once beaten on pure pace, as Lewis Hamilton and Nico Rosberg fought over the world championship all the way to the final race of the year.
With a few notable exceptions, the pattern has been repeated in 2015. Mercedes have again won all but three of the races and taken all but one pole position. Meanwhile, Ferrari's resurgence has seen them leap into second place; they look well-poised to take the fight to Mercedes in 2016.
But for the teams powered by Renault and Honda engines, the future doesn't look so bright. Despite being two of the world's largest car-making companies, these manufacturers got their V6 turbos horribly, horribly wrong.
The result has been a second year of misery for big-spending Red Bull and a disaster for McLaren. Drivers like Fernando Alonso, Jenson Button and Daniel Ricciardo have seen their hopes of success crushed in 2015—and there doesn't appear to be any light at the end of the tunnel.
Many fans are unhappy at the disparity between the four engines, and they're not alone. F1 commercial rights chief Bernie Ecclestone doesn't like it, nor do the teams suffering because their supplier made mistakes.
As a result, the engines have come in for a lot of criticism, and many people would be glad to see the back of them—and, to a certain degree, they have a point. The current state of affairs in F1 is unhealthy, and it should not be allowed to continue.
But the engines themselves are not the problem. They're wonderful pieces of engineering that have cemented F1's position as the most technologically advanced racing series in the world.
The engines are beautiful. The problem lies in the F1 rulebook pages devoted to listing the restrictions on their development—restrictions designed for a totally different situation to the one the sport finds itself in.
The decision to go with V6 turbo hybrid engines was officially made in mid-2011. After much discussion and disagreement about the direction the sport was to take—1.6 litre, four-cylinder engines were also mooted—the World Motor Sport Council gave final approval for the current engines to arrive from 2014 onward.
From that point on, the manufacturers could do as much research and development into the new units as their hearts desired. But from the start of the 2014 season, heavy restrictions on what they were allowed to do would apply.
Development would be frozen until the next winter, at which point they could make limited changes under the new "token system"—put in place as a cost-control measure with the agreement of all involved.
The power units were divided into 44 parts, with each part given a "weight" of between one and three tokens. The entire unit would "weigh" 66 tokens. Full details of the 44 parts and the number of tokens needed to modify each can be found in Appendix 4 to the 2015 Technical Regulations.
Between the 2014 and 2015 seasons, the teams would be given 32 tokens to spend on engine development. The following year, that would drop to 25, then 20 ahead of 2017, 15 for 2018 and three for 2019 and 2020.
Furthermore, each power unit would have to last for an average of four races in 2014, rising to five the following year. The taking of additional components beyond the limit of four would be punished by harsh grid-drop and in-race penalties.
The idea here was to stop the richer teams fitting expensive, shiny and unworn new engines whenever the fancy took them.
It sounded like a great idea at the time, and in fairness to those who came up with it, it was the right call to make. There was no way to make the complex new units cheap, but imposing development restrictions would (in theory) keep the prices down to halfway-manageable levels.
But the token system and in-season development freeze plan had a massive flaw. It was created on the assumption that all the engines would start out broadly similar—or at the very least, similar enough to be brought to near-parity by minor modifications that could be made within a highly restrictive framework.
An FIA guide published before the 2014 season explained this:
The most efficient way to reduce development cost is to stop it. This is known as a ‘freeze’. This was partially done with the V8 engines.
It works well with mature technologies but could be risky when imposed on new technologies, as it can lead to a team/manufacturer whose initial product is superior, leading to them achieving a dominant position from the outset and this domination would then naturally persist for the duration of any development freeze.
Therefore, we have set out a schedule that will keep costs down but still permit development.
Had everything gone as intended, we'd be sat here now applauding this approach—or rather, we wouldn't be mentioning it at all.
Unfortunately, things have not gone as intended. No one expected some manufacturers to be as far ahead as they are—or as far behind—so no one thought to include a back-up plan.
There was no mention of what would happen if one or more manufacturers needed to make wholesale changes to get anywhere near the class-leading engine—and unfortunately, that's exactly the scenario we've ended up with.
Mercedes are out ahead, and Ferrari, having fixed the relatively simple major issue with their 2014 power unit over the winter, are within striking range. For the leading two manufacturers, the token system is—by and large—working.
So, too, is the penalty system. No Mercedes-powered driver has exceeded his permitted number of power-unit components in 2015, while only two of the four Ferrari-powered drivers have.
But it's a very different story for Renault and Honda. Both made a complete hash of their power units and exist outside the FIA's ideal-world window. Within the current rules, neither look capable of developing their engines to anywhere near a competitive level until 2017 at the earliest—and possibly not even by 2018.
Such a situation was never meant to arise.
Their woes are being compounded by the penalty system. Designed to punish profligacy, it has instead become a stick with which to beat well-meaning teams and engine suppliers whose power units have, for whatever reason, turned out to be unreliable.
No Honda or Renault-powered driver has escaped these penalties—F1 Fanatic notes Fernando Alonso and Jenson Button, the "worst offenders," have each received more than 150 places worth of grid penalties. Daniel Ricciardo has also been heavily affected.
Again, this was never supposed to happen.
Some small concessions have been granted to the teams chasing Mercedes.
In-season development was allowed in 2015 after Ferrari spotted a loophole in the regulations, Honda were allowed an extra engine for the current season (five rather than four) and the penalty system was overhauled to remove in-race penalties.
Furthermore, the manufacturers will again have 32 tokens to play with in the coming winter, rather than the planned 25. In-season development will also be permitted.
But these changes are unlikely to be enough to give Renault and Honda a chance to catch up any time soon—and the teams at the top know that. In October, James Allen quoted Mercedes boss Toto Wolff saying, "give it two years and Renault and Honda are going to be competitive again."
It's nice of Wolff to have faith in them, but the sport cannot afford to keep two of its key suppliers locked into uncompetitiveness for that long.
In any walk of life, unexpected problems are solved by making changes. If the original plan isn't working, a new one must be quickly formulated. No one should rigidly stick to a path once it has become glaringly obvious that it's not leading to where they expected it to go.
We all point and laugh at truck drivers who blindly follow their sat-navs and end up stuck down a country lane or under a low bridge.
Why aren't we laughing at F1 for doing exactly the same thing?
Power-unit equalisation—as Christian Horner was calling for back in Australia, according to Autosport—would be the wrong call. Small variations between power-unit suppliers is healthy and should be seen as a positive for the sport.
But the gulf between the best and the worst should never be as great as it is today.
The two manufacturers struggling the most need to be given real opportunities to make improvements, and there are only two realistic ways to do that: either by awarding extra tokens to Renault and Honda, or by temporarily suspending the token system altogether.
It wouldn't be an ideal fix—the accountants would have a collective meltdown, and the smaller teams would understandably be concerned.
To protect them, any proposal that may increase costs for the engine manufacturers would need to be accompanied by a cap on the price of the units—the smaller teams should not shoulder the burden of development that will primarily benefit the "works" teams.
If a manufacturer wishes to make the most of their newfound freedom by throwing lots of money at their engine, let them—but the cost would be theirs to bear and the decision to invest would be theirs alone.
Mercedes would, with good reason, be a little grumpy. They earned their advantage through ridiculous amounts of hard work, time and money—it's reasonable for them to want to reap the benefits.
But they did that in 2014 and 2015. Two years of unopposed, enforced dominance is enough, and the marketing value of their success over the last two years puts the sums invested in creating their masterpiece of an engine in the shade.
BBC Sport's Andrew Benson reports the "global advertising value" of their exposure in 2014 alone was $2.8 billion (£1.83 billion).
For a company that enters F1 for one reason—promoting itself—that's a pretty good return, and it doesn't even begin to take into account the benefits to their road car divisions from the advances they have made in hybrid technology.
Nor does it touch on the "significantly increased revenue flows" they will receive, per Adam Cooper, from the commercial rights holder for winning two championships.
Their agreement would be needed to make this sort of change at short notice; hopefully, they'd feel more than ready for some proper competition.
The idea of holding one team back—or rather, giving more opportunities to certain teams to allow them to catch up—wouldn't go down well with many fans. As someone with a genuine, long-standing passion for the sport and an innate preference for fair play within the rules, this writer is one of them.
And no one would dispute that the only ones to blame for Renault and Honda's current struggles are Renault and Honda themselves.
But the engine-development regulations were dreamed up and written for a very different world to the one we find ourselves in—and regardless of who is to blame, the mistakes those manufacturers made are adversely impacting on our enjoyment of the sport we love.
Who loses out from seeing great drivers like Alonso and Button pootling around in 15th and 16th?
It would be hard to disagree with anyone who said that poking and prodding around in an established set of laws in order to artificially hand opportunities to some manufacturers, but not others, wouldn't really be right.
But blindly sticking to restrictions that are clearly unsuitable and are enforcing a lack of competitiveness throughout the order would be far, far worse.