An example of this which certainly everyone will recognize is in the ``Doom''-style games, where walls are drawn using stone or metal patterns instead of single colors. These program start off with small images of those patterns (called textures), and then cover the walls with these images. This covering is called a mapping because it maps pixels from the image onto the points comprising the walls. Texture mapping is much slower than assigning a single color to every object, since it requires determining and then fetching the appropriate texture pixel corresponding to every point we draw. It has become very common in the last few years, however, thanks to advances in processor speeds and faster graphics algorithms.