Шэнь Ко
Intellectual men of letters like the versatile Shen Kuo dabbled in subjects as diverse as mathematics, geography, geology, economics, engineering, medicine, art criticism, archaeology, military strategy, and diplomacy, among others. On a court mission to inspect a frontier region, Shen Kuo once made a raised-relief map of wood and glue-soaked sawdust to show the mountains, roads, rivers, and passes to other officials. He once computed the total number of possible situations on a game board, another time the longest possible military campaign given the limits of human carriers who would bring their own food and food for other soldiers. Shen Kuo is also noted for improving the designs of the inflow clepsydra clock for a more efficient higher-order interpolation, the armillary sphere, the gnomon, and the astronomical sighting tube; increasing its width for better observation of the pole star and other celestial bodies. Shen Kuo also experimented with camera obscura, only a few decades after the first to do so, Ibn al-Haytham (965–1039).