Many years ago, Francois Gennedy ran a used hot rod concession out from behind his house. His sizeable property held a rather tame collection of project cars, donor cars and parts. With one exception, there was an engine in there that Francois claimed would run 100 km on a single litre of gas.
Legend surely, but Francois had once worked for a major automobile manufacturer, or so he claimed, which had purchased his patent and sat on it, leaving Francois with only his demo engine (he'd given them a copy, claiming it was the only one, which the company promptly destroyed).
Under a stack of legal documents that would punish him with worse than death should he circumvent the wishes of the company, Francois had hidden the engine somewhere in his back yard and did his best to forget where.
Or so he claimed. Many people tried to find that engine without success, then one day, Francois disappeared without a trace.
A quarter century and several passports later, my collegue, Frank Kennedy, confessed that he was actually Francois Gennedy.
I didn't believe him of course, if the Frank Kennedy I knew was in fact the legendary Francois, he should have been 103 years old. Frank Kennedy was a well preserved 57 despite his habit of chain-smoking.
He explained that the engine worked on future-fuel. I asked him what he meant.
"You see, I figured that if there is such a thing as multiple dimensions, I realized it didn't mean they ran perfectly in sync. Things could happen here and now but one step left or right, here and now could be then and there. So I built an engine on the theory that all the fuel it would ever use potentially, must be in use right now in one dimension or another"
"You lost me after the word dimension,"
"Forget the theory side, the practical upshot is I built an engine that would run it's entire lifetime on a single litre of petrol while emitting exhaust gasses backwards in time,"
I was certain Frank had had too much to drink, yet the more I protested and poked holes in his nonsense the hotter he got under the collar.
"Dammit! I'll show you! Let's take a drive,"
Frank's car was so unspeakably ordinary, it slid off the memory banks like a cash withdrawal. Even the colour was indescribably mundane.
"Boredom personified, isn't it? I'm especially fond of my rust job," Frank indicated the places on the body where, for reasons never fully explained, he had carefully painted the body with browns and reds so the car appeared older and more used than it actually was.
I admitted that the paintwork was realistic. Frank pointed out other aspects of how he had weathered, stressed and antiqued the body.
I finally asked him why.
He answered by opening the passenger door.
You'd never believe the places we went, the adventures we had, I won't try to describe them.
Frank Kennedy told the truth, yet less than the whole truth.
In his car, the further you went, the younger you got, the further into the past you travelled.
The emissions travelled faster, stopping in the carboniferous period.
That's why I had to kill him.
The Company would never tolerate such a machine to exist. It would upset our alien overlords to no end.