Back in 1969, Porsche had some big problems. Their new, highly advanced racecar, for all its sophisticated features (gas-pressurized spaceframe, exotic-alloy air cooled flat-12, balsa wood shift knob) kind of, um, sucked. It handled horribly, being called "incredibly unstable" by one of Porsche's factory drivers.
The car was quite fast, but no amount of tinkering with the suspension and frame seemed to make any difference to improve the car's handling. The 1969 racing season turned out to be a bust for Porsche, since they had a very fast car that couldn't be controlled, even to the point of causing the death of one of their privateer drivers.
The next year, the official Porsche team (formerly the JWA Gulf Team) was testing the car at what's now known as the Red Bull Ring, when the chief engineer, John Horsman, noticed an odd detail. The car was covered with a pattern of squashed gnats, a pattern that revealed the airflow over the car. The tail of the car, however, was gnat-carcass free, suggesting that no air was flowing over the tail, which was causing the pronounced lack of downforce that was key to the car's handling woes. At the time, the importance of downforce wasn't really understood, but that lack of gnats was certainly suggesting something important.
Horsman had a new tail rigged up in the pits with aluminum sheets secured with tape. The new tail that was hacked together improved the car's handling dramatically, and the drivers were able to achieve much better results in testing. The new shorter tail was incorporated into a redesign and became the 917 K, with the ‘K' standing for Kurzheck, or "short" in German. Even though the new tail looks longer, at least to me.
I'm sure nowadays they have sophisticated computerized gnat simulators, with the ability to project synthesized holographic gnat images right onto prototype bodies. So the next time you swallow or blink a cold, cold gnat in your eyelid, give a little thought to all that gnats have given motoring.