Most QLB peoples live in flat-roofed, multistory dwellings built of unwrought stone. The ground floor is reserved for livestock and the collection of compost, while the second story, which contains the hearth, functions as the main living/sleeping space. The hearth, a square section in the middle of the floor equipped with a three-legged cooking frame, is sacred, and is associated with a rigid seating order. The third story contains a large open area used as a threshing ground and meeting place; it usually also contains storage rooms, extra sleeping quarters, and an altar. There are no chimneys. Smoke from the hearth escapes through a hole in the roof. In Qiang settlements, which are fairly typical of areas on the eastern rim of the corridor, houses are built in close defensive groups on the mountainsides, often in conjunction with stone towers 30-50 meters high. Villages vary considerably in size, averaging around twenty households; they may occur in clusters of two or three, surrounded by fields. Separate clusters are distributed at intervals of 1.5 to 2 kilometers along the valley walls below treeline, frequently above steep cliffs, with valley bottoms often being relegated to Han Chinese settlements. Jiarong villages are higher (2,000-3,400 meters), more widely separated, larger, and more diffuse, often stretching from the valley bottoms up the slopes. Houses may be separate and are sometimes clustered in small, named neighborhoods of three to eight households. Jiarong villages typically contain a fortress with tower and a Lamaist temple.