"Ebb and Flow" is a 55-meter animated light installation on Marine Gateway's 29th storey south tower façade. It connects us to Vancouver's maritime environment by visualizing the twice-daily rise and fall of the local tide. A glowing white light glides up and down the "scale" of the tower, backed in green light as the tide goes out (ebb), then changing to blue as it comes in (flow). As the tide shifts, the faint trail of white light tells you if it is rising or falling. Each two floors of the building represent roughly one foot of tide height.