Building Materials and Construction Components Design Karst Water Filtration Staircase by Chi-Hao Chiang Karst, a modular staircase designed for Governors Island in New York, is like a solutional cave for people to see and hear the flowing water, with a water filtering system that brings the sensation of nature into the house, connecting the community of humans and water. Each module has a pocket for placing a bag of crushed oyster shells. The shells composed of calcium carbonate can react with acid rain to help neutralize acidified ocean by absorbing carbon dioxide. In the end, it is a filter system that can blur the boundary between humans and nature on Governors Island.