A rectangular lintel spans the windows in the ubosot (ordination hall). Subtleties include a bottom-to-top taper which widens again very slightly towards the top of the frame; a projecting sill at the bottom of the window; and a wide thin lintel at the top of the window. Tapezoidal window openings stabilize the top lintel and create an illusion of extended height. Similar windows can be found in the precolumbian Andes, and in India.