M18 Maison de Ville is a minimalist space located in Toulouse, France, designed by BAST. The designers were tasked in implementing a spiral staircase constructed in concrete. The staircase is characterized by an array of identical vertical pillars that extend with no other support. The pillars serve as both the handrail and barrier to prevent falls. The pillars, which are opposite the main windows, play along with light and shadows that pass through, creating a series of obelisks.