The ancient Egyptians utilized headrests to support a person's neck while sleeping. While the flat base board and curving top are constant elements, the center section's shape varies. This style is quite uncommon, with six slender rods supporting the curving top. The center section is usually made of wood but may also be of stone or metal. There are two different types of headrests in use today: the pharaonic and the modern. The pharaonic headrest is similar to the one used by the Egyptians, except that it has three rather than six supports. It is still used in some African countries such as Senegal and Mali for bedding. The modern headrest consists of a wooden block supported on four legs. It is used throughout most of the world but particularly in North America. Headrests can be constructed out of many materials including steel, wood, and plastic. However, only wooden headrests are designed to be taken off and put back on. This is important because it allows for cleaning or replacement of the material used. People who sleep on headrests may experience neck pain or stiffness due to improper positioning of the head when lying down or getting up. Sleeping on a headrest may also affect your quality of sleep if it causes you to toss and turn or if its design does not allow for comfortable sleeping.