In architecture, a coffer (or coffering) is a sequence of recessed panels in the shape of a square, rectangle, or octagon in a ceiling, soffit, or vault. They provide an aesthetic alternative to plain ceilings and also help diffuse light from lamps below. Coffers are used in many different types of buildings, both old and new. Some examples include churches, cathedrals, museums, theaters, concert halls, art galleries, private collections, and libraries. Coffered ceilings are popular because they add visual interest and texture to an otherwise bland ceiling plane. They are created by starting with a flat surface and then creating a series of parallel grooves on each side. The depth of these grooves can be the same width as the panel itself or it can be less if you want the effect to be more pronounced. After all the grooves have been cut, each panel is lifted up and attached to the next with small brackets or nails. Finally, any visible cracks between the panels are filled with plaster or another similar material and painted if desired. The word "coffer" comes from the Latin word cubiculum which means "a room". Thus, a coffer room is a large room with coffered ceilings. Coffered ceilings are much easier to create than you might think.