Resumen de Machine made.
The article discusses the findings that intricate carvings on the best jades from ancient China were evidently etched by compound machines at least three centuries before such devices were thought to be invented in the West. The first historical references to compound machines, which employ several forms of movement, do not occur until first-century A.D. writings credited to Hero of Alexander. Harvard University physics graduate student Peter Lu looked at ornamental jade burial rings from the Spring and Autumn period (771 to 475 B.C.) and found that the uniformity and precision of their grooves -- some conforming within 200 microns of ideal Archimedean spirals -- strongly argue for origins in compound machines.
