I'm going to disagree with a couple of the famous Aussi inventions listed above. I don't know if staysharp is a trade name or just the generic term for a knife that doesn't require sharpening, but the latter was developed in the late 50's - early 60's by a pair of scientists or engineers from Dartmouth College, who had done a lot of work with plasma torches in the mid 50's.   They'd knocked up a bunch of kitchen knives with a thin coating of tungsten carbide sprayed onto one side of the blade of a cheap kitchen knife, as a souvenir of a visit to their plant. As the blade wore, the thin tungsten carbide layer became the cutting edge. The second was the multiple focus contact, if I understood the concept correctly. These were available in the UK back in the early 70's, so could not have been invented by the Aussies in '92.

Dave