As part of the Grand Paris Express Project, this building will serve as a place for daily activities encompassing three types of urban "density". First, the "density" from below – representing the citizens from stations of the Grand Paris Express Project. Second, the "density" above ground, comprising residents of social housing planned by the government. Finally, the "density" at ground level, referring to the social activities of the inhabitants. This design actively explores the potential of "artificial nature" as a "medium" to facilitate interaction among groups within and around the site.