For three days in early October, the 2016 Market Street Prototyping Festival gave the public a chance to experience more than three dozen ideas for enhancing San Francisco’s main drag and creatively engaging people with the urban environment and with each other. Created by teams who answered a call for submissions last April, the installations ranged from an artistic ping-pong table to an enclosure containing homemade musical instruments to a hand-crank-powered box that distributed stories and artwork. Kuth Ranieri’s contribution, SonoGROTTO, was a pavilion made of hundreds of cardboard tubes, carved to create seats, windows, and an oculus that frames views to the sky.