Motion graphics are graphics that use video footage and/or animation technology to create the illusion of motion or rotation, graphics are usually combined with audio for use in multimedia projects. Motion graphics are usually displayed via electronic media technology, but may be displayed via manual powered technology (e.g. thaumatrope, phenakistoscope, stroboscope, zoetrope, praxinoscope, flip book) as well. The term is useful for distinguishing still graphics from graphics with a transforming appearance over time without over-specifying the form. Motion graphics extend beyond the most commonly used methods of frame-by-frame footage and animation. Computers are capable of calculating and randomizing changes in imagery to create the illusion of motion and transformation. Computer animations can use less information space (computer memory) by automatically tweening, a process of rendering the key changes of an image at a specified or calculated time. These key poses or frames are commonly referred to as keyframes. Adobe Flash uses computer animation tweening as well as frame-by-frame animation and video.