I'm interested in special purpose machines - it's amazing how creative people can be in solving special problems - this particular machine
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) is used for packing dental amalgam into a cavity (I'm linking to an ebay auction because there are pictures there and a link to the patent which shows in detail how it works) - now I find this machine interesting - it uses a pulsating column of air (the thing that looks like a compressor isn't REALLY a compressor, per-se) to make a hardened steel pin oscillate, which in turn, under the right circumnstances hits a linkage that makes the little ram tap on the amalgam.
I don't know, I find it really really clever - first, to decide that tapping on the amalgam was a good thing, second to design this thing with a column of air so there is no risk of electrical shock, and then getting all the forces in balance so it actually works, taps on the amalgam without smashing it through the tooth, and so on. I have a number of patents to my name, but I think this one is just plain clever - not necessarily "brilliant" (the geosynch satellite was brilliant) but very clever.