@deshipu I'd definitely like to see those, especially that the other two you have aren't convincing either. I know little about Mesoamerica, but the Greek steam engine was a machine barely deserving the name, built in an environment where they weren't able or willing to make further progress on the technology.
This is to say, my current belief is: any technology that can be put to military use *is* put to military use. Cases like Greek "steam engine" are when technology isn't mature enough to be useful.
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