Most modern mice use optical movement detection with no moving parts. Later, the standard design shifted to use a ball rolling on a surface to detect motion, in turn connected to internal rollers. Mice originally used two separate wheels to directly track movement across a surface: one in the X-dimension and one in the Y. The first public demonstration of a mouse controlling a computer system was in 1968.
This motion is typically translated into the motion of a pointer on a display, which allows a smooth control of the graphical user interface of a computer. A computer mouse (plural mice, also mouses) is a hand-held pointing device that detects two-dimensional motion relative to a surface.
