This Pan Gong stone was shaped by water and sand over thousands of years in a river in Gansu province in northwestern China. Standing on end, the stone reminds us of some of the sharply rising mountains in western China. Or, it could be one side of a steep canyon wall moist with dripping water after the sun has dropped below the horizon. Lingering in a narrow canyon as the sun is setting can reveal some beautiful light patterns and colors, but darkness comes quickly to these canyons for those who overstay their visit. The stone is 40 cm high, 38 cm wide and 18 cm deep, weighs nearly 50 kilograms, and is in the collection of Tom Elias and Hiromi Nakaoji.