In computer graphics, an undesirable effect—also known as jaggies—in which the edge of an image is characterized by a stair-step appearance. Aliasing occurs when the edge of the image is offset to the closest available pixel, and an edge consisting of many small alternating horizontal and vertical lines results. Thus, straight lines (or more commonly diagonal or curved lines) on a computer monitor or low-resolution output device are only approximately straight. Aliasing can be rectified by anti-aliasing, or the partial lighting of intermediate pixels. (See Anti-Aliasing.) Aliasing is also known as stair-stepping.