For the side walls this tiled type of construction is commonly used (Plate LXXVIII). A coarse bamboo mat is likewise employed, while a crude interweaving of bamboo strips is by no means uncommon. Such a wall affords little protection against a driving rain or wind, but the others are quite effective. Well-to-do families often have the side walls and floors of their houses made of hard-wood boards. Since planks are, or have been until recently, cut out with knives, head-axes, or adzes, much time and wealth is consumed in constructing such a dwelling. When completed, it is less well adapted to the needs of the people than the structures just described, but its possession is a source of gratification to the owner, and aids in establishing him as a man of affairs in his town. The floor is made of poles tied to the side-beams, and on these strips of bamboo are laid so as to leave small cracks between them. This assists in the house-cleaning, as all dirt and refuse is swept through the openings on to the ground. When the floor is made of wood, it is customary to leave one corner to be finished off in the bamboo slits, and it is here that the mother gives birth to her children. This is not compulsory, but it is custom, and indicates clearly that the planked floor is a recent introduction. Entrance to the dwelling is by means of a bamboo ladder which is raised at night, or when the family is away. Windows are merely square holes over which a bamboo mat is fitted at night, but the door is a bamboo-covered framework which turns in wooden sockets. Such a house offers no barriers to mosquitoes, flies, flying roaches, or white ants, while rats, scorpions, and centipedes find friendly shelter in the thatch roof. Quite commonly large but harmless snakes are encouraged to take up their residence in the cook room, as their presence induces the rats to move elsewhere. Little house lizards are always present, and not infrequently a large lizard makes its home on the ridge pole, and from time to time gives its weird cry. The ground beneath the house is often enclosed with bamboo slats, and is used for storage purposes, or a portion may be used as a chicken coop. It is also customary to bury the dead beneath the dwelling, and above the grave are the boxes in which are placed supplies for the spirits of the deceased.