Marvin pulled up a map. "Speaking of which—sort of—I found the flint source. One of the old villages. And interestingly, there’s some worked flint there and in a couple of villages nearby. I think at least some of the Deltans have known what to do with it, so Archimedes isn’t unique." Marvin looked around at us to make sure we would get his next comment. "I think there’s a recessive gene for increased intelligence that’s spreading through the population. It just needs the opportunity to be expressed, in every sense of the word."