There's an Alan Moore short story early in his career that he declined to have reprinted because he realized after he'd written it that he'd inadvertently ripped off Lafferty. The story concerns a man who builds a machine that lets him go slightly back in time, which he uses to his advantage at a casino, but who is then thwarted by a coat attendant with a "probability manipulator." I'd love to track down the original Lafferty story. Does it ring a bell?
Answered below, but wanted to make sure all the content was posted. Do you recall which Moore story that was? Would be interested in seeing that influence, however unintended.
Alan told me about this — the story is a chapter from Space Chantey — the Wrong Prong Bong Gong chapter.
Yes, with the rather eccentrically named “dong button,” which I guess is what happens when you let a Laestrygonian-Norse kid giant name all your devices.