From the first phase of the Blue Ocean, the second phase of Hainachuan, to the third phase of Haydn, this series of collective housing attempts to combine architecture with water and mountain views. In the works of the first two issues, arcs were used to reflect the surrounding Tamsui River culture, and the appearance of the building was shaped with wave curves. Haydn’s base is located on the right side of the blue ocean, close to the Datun Mountains. We chose to incorporate the image of the mountains in the design. The design continues the vocabulary of the curved balcony, and uses clear green glass and dark green stone decoration to make the whole building echo the mountain background. We invert the glass handrails and surround the plane outer ring in the form of a vertical wall, so that it can maintain the penetrability of the balcony section and achieve the continuity of the indoor and outdoor spaces.