Installation is wrapping up on the limestone panels that clad the exterior. The panels reference the Indiana limestone cladding of nearby Rockefeller Center, a precedent for the design team. Smooth limestone panels are interspersed with textured limestone panels that resemble the vertical lines of the bush hammered concrete facades of nearby buildings. The subtle detail helps to avoid a monolithic appearance on the facade. Apart from aesthetics, the exterior wall contributes to the sustainable design strategies of the building, as the deep stone exterior walls create a thermal mass that helps moderate temperatures extremes in the summer and winter. Zinc panels with a vertical pattern clad the circulation core at the east elevation as well as the spandrel areas above the windows on the penthouse floors.