Yes its strange to think, under guild systems of suspicion and secrecy, that anything like these amazing contrivances could be designed and built. Were these Newton-grade geniuses? Skilled mechanics? Nerds of another age?

Just saw a so-so documentary on glass, which included the insight that Venice has had glass guilds for 500 years. During the whole time they've flourished under a system of knowledge sharing, where the old masters taught anyone (in the guild) who would listen, their techniques. Made Venice an amazing place, for glassmaking and lensmaking.