Curtain Door, Surat, India by Matharoo Associates
At 5.2m high and 1.7m wide, the door is comprised of 40 sections of 254mm-thick Burma teak. Each section is carved so that the door integrates 160 pulleys, 80 ball bearings, a wire-rope and a counter weight hidden within the single pivot. Stacked one above the other in the closed position, each plank can then rotate by a simple push causing the door to reconfigure into a sinusoidal curve.
via The Architectural Review