Our proposal for a mixed-use tower began with concepts of fluctuation and connection, responding to the nearby but often-neglected East River waterfront. Formed conceptually by lifting up a volume of water equal to that displaced by a proposed new pier, the tower’s mass is anchored equally to water and sky. The central challenge of the project was to create a real, constructible solution for an exceptional live/work environment on an extremely constrained site. The solution is a combination of two overlapping structural systems that inverts the common wisdom of high-rise design, allowing a light, glassy skin near the commercial base and a solid, high-performance envelope in the upper, residential portion. At the base, an efficient “pinwheel” structure permits maximum transparency in the façade while simultaneously organizing the interior space; above, the solid envelope acts as a moment frame while improving both energy performance and residents’ privacy. The tower’s façade is mixed composition of transparent and opaque surfaces, informed by study of the river and its ever-changing expressions.