communicating information and command selections to processor 1904 another type of user input device is cursor control 1916 such as a mouse a trackball or cursor direction keys for communicating direction information and command selections to processor 1904 and for controlling cursor movement on display 1912 this input device typically has two degrees of freedom in two axes a first axis e g x and a second axis e g y that allows the device to specify positions in a plane computer system 1900 may implement the techniques described herein using customized hard wired logic one or more asics or fpgas firmware and or program logic which in combination with the computer system causes or programs computer system 1900 to be a special purpose machine according to one embodiment the techniques herein are performed by computer system 1900 in response to processor 1904 executing one or more sequences of one or more instructions contained in main memory 1906 such instructions may be read into main memory 1906 from another storage medium such as storage device 1910 execution of the sequences of instructions contained in main memory 1906 causes processor 1904 to perform the process steps described herein in alternative embodiments hard wired circuitry may be used in place of or in combination with software instructions the term u201c storage media u201d as used herein refers to any non transitory media that store data and or instructions that cause a machine to operate in a specific fashion such storage media may comprise non volatile media and or volatile media non.