Using space normally left unoccupied best describes the strategy at the heart of Matheus Rocha Pitta’s recent exhibition “Nau,” whose title is an archaic Portuguese word for ship. Rather than deploy the existing architecture to display his work, the artist installed scaffolding topped off with a plywood floor in Galeria Progetti’s atrium space, creating a surface level with the building’s second floor. Viewers had to climb some stairs to this provisional viewing platform in order to access twelve framed photographs, each ten by seven-and-a-half inches and taken with a cell phone. All of them