a detailed description of one or more embodiments of the invention is provided below along with accompanying figures of illustrative embodiments of the invention . the invention is described in connection with such embodiments , but the invention is not limited to any embodiment . the scope of the invention is limited only by the claims and the invention encompasses numerous alternatives , modifications and equivalents . specific details are set forth in the following description in order to provide a thorough understanding of the invention . these details are provided for the purpose of example , and the invention may be practiced according to the claims without some or all of these specific details . for the purpose of clarity , technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured . a user of a computer , such as a personal computer , a desktop computer , a portable computer , or a laptop , may often carry a separate pointing device , such as a mouse , even if the computer is equipped with a built - in pointing device , such as a touch screen or a touch pad . the accuracy , such as resolution , and the ergonomics of built - in pointing devices is sometimes less than desired by the user . carrying a separate pointing device can be inconvenient . furthermore , in situations where two or more people want to share control of an application on the computer , such as a multi - player gaming application , only the owner of the computer may have access to a pointing device . a type of device that is frequently carried , independent of carrying a computer , is a cellular communication device . in some embodiments , incorporating pointing device functionality into a cellular communication device enables access to a pointing device in situations where a pointing device is not otherwise available , with greater convenience , and / or with operational advantages . in further embodiments , the cellular communication device including pointing device functionality is configured to communicate wirelessly with the computer . in some usage scenarios , multiple pointing devices , including at least one cellular communication device , are configured to communicate wirelessly with a computer , enabling multiple users ( players ) to control a single application ( such as a gaming application ). while parts of the description below refer to the pointing device as a mouse , various embodiments use different types of pointing devices , alone or in combination . devices or systems referring to , or referred as , a cellular communication device may be understood as being applicable to various types of cellular devices and communication devices known in the art , such as personal digital assistants ( pdas ), cellular telephones , pagers , etc . in a first example embodiment , a device includes cellular communication device functionality , a sensor , such as an optical or mechanical position sensor , and a wireless transceiver ( independent of a transceiver used for the cellular communication device functionality ). the sensor is enabled to report position information , such as relative position information , to a computer via the wireless transceiver , allowing a user of the device to interact with and / or to control the computer . in a second example embodiment , a device includes cellular communication device functionality , a touch screen , and a wireless transceiver ( independent of a transceiver used for the cellular communication device functionality ). the touch screen is used to interact with and / or to control the cellular communication device functionality . additionally , the touch screen is used as a wireless touch pad to interact with and / or to control a computer via the wireless transceiver . the second example embodiment does not require a position sensor as the touch screen provides the pointing ( movement ) information used to interact with and / or to control the computer . in various embodiments , such as either of the first example embodiment or the second example embodiment , some of the input mechanisms ( such as buttons , wheels , joysticks , or touch screens ) of the device are enabled to interact with and / or to control the cellular communication device functionality . the input mechanisms are additionally enabled , optionally in an operating mode , to interact with and / or to control a computer via the wireless transceiver . for example , a particular one of the buttons of the device is used to initiate a communication device call when the device is operating as a cellular communication device , and the particular button is enabled to operate as a left mouse button when the device is operating as a wireless pointing device . fig1 illustrates selected details of an illustrative embodiment of a system including a wireless adaptor and a device operable as a cellular communication device and as a wireless pointing device . computer 110 includes and / or is coupled to wireless adaptor 112 . in some embodiments , wireless adaptor 112 is built into computer 110 , such as by being on a motherboard of computer 110 . in further embodiments , wireless adaptor 112 is integrated with other portions of computer 110 in an integrated circuit , such as by being a portion of a southbridge chip or chipset . in other embodiments , wireless adaptor 112 is connected via a peripheral interconnect , such as a personal computer memory card international association ( pcmcia ) slot , a universal serial bus ( usb ) slot , a peripheral component interconnect ( pci ) slot , or another computer peripheral interconnection . wireless adaptor 112 enables computer 110 to communicate over wireless interconnect 114 with one or more devices , such as device 120 and optionally device ( s ) 160 . in some embodiments , device 120 is a device including cellular communication device functionality and wireless pointing device functionality . the cellular device functionality enables communication via device 120 over a particular cellular network . according to various embodiments , devices ( s ) 160 are one or more of : a same type of device as device 120 and enabled to communicate via the particular cellular network ; a same type of device as device 120 and enabled to communicate via a different cellular network ; a different type of device from device 120 , such as a wireless keyboard , a wireless mouse , a pda , or a pager ; and any other communication device . in some embodiments , wireless adaptor 112 is adapted to communicate with computer 110 using a protocol , such as universal serial bus ( usb ), peripheral component interconnect ( pci ), or another protocol for peripheral interconnection . devices 120 , 160 are enabled to communicate with wireless adaptor 112 using respective local wireless transceivers ( such as wireless transceivers internal to devices 120 , 160 ) over wireless interconnect 114 . ( in various embodiments , the local wireless transceiver is part of a wireless logic function , such as wireless logic 224 including transceiver 225 as illustrated in fig2 b .) wireless interconnect 114 uses a protocol that is optionally different from the protocol between wireless adaptor 112 and computer 110 . devices 120 , 160 are enabled to communicate with the respective local wireless transceivers using protocol that is optionally different from the wireless interconnect protocol . in one example , wireless adaptor 112 is adapted to communicate with computer 110 using a usb protocol , and wireless interconnect 114 uses a bluetooth protocol . in another example , wireless interconnect 114 uses a wireless usb protocol , and device 120 is enabled to communicate with the respective local wireless transceiver using a usb protocol . in some embodiments , wireless adaptor 112 uses a wireless usb protocol operating at 2 . 4 ghz , and is adapted to communicate using a direct sequence spread spectrum ( dsss ) technique to avoid interference from other 2 . 4 ghz technologies , such as bluetooth or 802 . 11 . for example , in various embodiments , wireless adaptor 112 uses a cypress semiconductor cyrf6936 chip , which provides a single - chip wireless usb solution and enables point to multi - point ( a usb host to one or more devices ) operation . in some usage scenarios , wireless usb provides a non - networking solution with lower overhead than networking solutions such as bluetooth , while providing a point to multi - point capability . information on cypress semiconductor &# 39 ; s proprietary wireless usb standard is available from a web site at wirelessusb . org . when one or more devices , such as devices 120 , 160 , communicate with computer 110 over wireless interconnect 114 , the one or more devices are enabled to communicate at substantially a same time . in some embodiments , communications of the one or more devices are interleaved at a fine - grained level , such as at a packet level , on wireless interconnect 114 so that each of the one or more devices communicates serially with computer 110 , but for practical purposes , the result is communication substantially at a same time . device 120 includes antenna 138 . in some embodiments , device 120 includes a cellular wireless transceiver coupled to antenna 138 . ( in various embodiments , the cellular wireless transceiver is part of a cellular logic function , such as cellular logic 228 including transceiver 229 as illustrated in fig2 b .) the cellular wireless transceiver and antenna 138 enable device 120 to communicate over cellular interconnect 128 with a cellular network and thus to operate as a cellular communication device . the cellular interconnect couples device 120 to cellular relay 190 , a cellular base station , or another type of gateway to the cellular network . in some embodiments , antenna 138 is an internal antenna . in other embodiments , as illustrated in fig1 and in others of the figures , antenna 138 is an external ( protruding from the otherwise roughly box - shaped device ) antenna . in some embodiments , antenna 138 is used for communication over both cellular interconnect 128 and wireless interconnect 114 . in further embodiments , antenna 138 illustrates a housing for a plurality of antennas , and a first one of the plurality of antennas is used for communication over cellular interconnect 128 , and a second one of the plurality of antennas is used for communication over wireless interconnect 114 . in other embodiments , device 120 includes a separate antenna ( such as antenna 227 as illustrated in fig2 b ) for communication via the respective local wireless transceiver . in further embodiments , the separate antenna is internal . for example , in various embodiments , the separate antenna is integrated onto a printed circuit board inside device 120 . in various embodiments , device 120 includes a sensor enabled to track movement of device 120 . as illustrated in fig1 , when device 120 is moved via motion 180 to the position indicated by device 120 ′, such as via sliding device 120 on a tracking surface , the sensor , via tracking 124 , is enabled to detect and to report the movement . in some embodiments , the sensor is an optical sensor , such as a laser navigation sensor , and tracking 124 represents illumination provided by the sensor . in other embodiments , the sensor is a mechanical sensor , such as a trackball . various types of sensors are compatible with other aspects of the techniques herein . for example , the sensor could be implemented , at least in part , by a cypress semiconductor cyons1001 single - chip laser navigation sensor . a laser navigation sensor provides a high degree of accuracy , such as sensing rate of more than 2000 counts per inch , and fast tracking speeds , such as up to 50 inches per second . in some embodiments , the sensor is enabled to report relative position information of device 120 over wireless interconnect 114 to computer 110 . that is , as device 120 is moved , the sensor is enabled to report movement relative to a previous position of device 120 . for example , as device 120 is moved , a delta in an x direction and a delta in a perpendicular y direction are reported . in some embodiments , device 120 includes a touch screen . motion information input by a user via the touch screen is reported over wireless interconnect 114 to computer 110 . in further embodiments , device 120 does not include a sensor for tracking motion of device 120 , and the touch screen is configured to provide motion information to computer 110 . device 120 includes one or more input mechanisms , such as button 132 . button 132 is representative of a variety of input mechanisms , such as buttons , navigation sticks , scroll wheels , keyboards , keypads , touch screens , virtual ( on - screen ) controls , and other input mechanisms . ( further embodiments of input mechanisms are described with regard to fig2 c .) button 132 is used , at least in part , to control operation of device 120 . button 132 optionally and / or selectably operates in different modes . for example , in a communication mode , button 132 operates to control cellular communication device operation of device 120 , and in a pointer mode , button 132 operates as a mouse button in conjunction with use of device 120 as a wireless mouse . in some embodiments , functionality of various ones of the input mechanisms of device 120 is configurable by a user of device 120 . in various embodiments , device 120 has one or more modes of operation , such as a cellular communication device mode and a wireless mouse mode , and functionality of one or more of the input mechanisms of device 120 is dependent on a current one of the modes of operation . in some embodiments , device 120 is enabled to transfer files , such as files resident on device 120 , to or from computer 110 over wireless interconnect 114 . according to various embodiments , the files are transferred under control of one or more of : computer 110 ; a controller of device 120 ( such as cpu 226 as illustrated in fig2 b ); and a user of device 120 . in one example embodiment , device 120 includes a camera , and at least some of the files are pictures . in another example embodiment , device 120 includes a music player , such as an mp3 player , and at least some of the files are digitally recorded songs . in yet another example embodiment , device 120 is enabled to execute user applications , such as a calendar , a word processor , or a spreadsheet , and at least some of the files are data files and / or documents associated with the user applications . fig2 a illustrates selected details of an offset bottom view of an illustrative embodiment of a device operable as a cellular communication device and as a wireless pointing device . in various embodiments , device 121 is the same as device 120 ( as illustrated in fig1 ). in some embodiments , device 121 includes one or more feet 282 . feet 282 provide a way to enable device 121 to slide more easily on a tracking surface , such as tracking surface 280 as illustrated in fig2 b . while fig2 a illustrates four feet , any number of feet , including zero feet , is optionally used in different embodiments , depending on mechanical , material , optical , and other constraints and / or relationships . in various embodiments , the number , size , height , and / or nature of the feet vary with a type of sensor , if any , used in device 121 , such as whether a motion tracking sensor is mechanical or optical . the illustrative embodiment of fig2 a uses an optical sensor as a motion tracking sensor ( to provide tracking 124 , as illustrated in fig1 ). the bottom of device 121 includes window 248 , such as a transparent or translucent glass or plastic window , and lens 244 for the optical sensor located in device 121 . for example , in some embodiments , the window enables an integral light source to illuminate the tracking surface , and the lens focuses reflections from the tracking source on an optical detector . fig2 b illustrates selected details of a cut - away side view of an illustrative embodiment of a device operable as a cellular communication device and as a wireless pointing device . according to various embodiments , device 122 is the same as one or more of device 120 ( as illustrated in fig1 ), and device 121 ( as illustrated in fig2 a ). device 122 includes a motion tracking sensor . in some embodiments , the motion tracking sensor comprises an optical sensor , such as optical sensor 241 . the optical sensor includes chip 242 and lens 244 , and is mounted on sensor printed circuit board ( pcb ) 240 . some chips , such as the cypress semiconductor cyons1001 , include an integrated vertical - cavity surface emitting laser ( vcsel ) light source and an optical detector . with a chip such as the cyons1001 , a lens and some discrete components such as capacitors and resistors provide for a complete optical sensor . device 122 further includes cellular logic 228 , wireless logic 224 , and a controller such as central processing unit ( cpu ) 226 . in some embodiments , cellular logic 228 includes cellular wireless transceiver 229 , and is coupled to antenna 138 , enabling device 122 to communicate over cellular interconnect 128 with a cellular network . in some embodiments , wireless logic 224 includes local wireless transceiver 225 , enabling device 122 to communicate over wireless interconnect 114 . in various embodiments , antenna 138 ( or one of a plurality of antennas inside a housing illustrated by antenna 138 ) is used to communicate over wireless interconnect 114 . in other embodiments , wireless logic 224 includes separate antenna 227 for the local wireless transceiver . for example , in some embodiments , the separate antenna is integrated onto a printed circuit board containing wireless logic 224 . a controller , such as cpu 226 , is illustrative of one of many possible ways in which electrical and / or electronic components of device 122 are interconnected . for example , according to various embodiments , one or more of cellular logic 228 , wireless logic 224 , and the optical sensor have respective controllers , and the respective controllers are optionally and / or selectably coupled together . in the illustrative embodiment of fig2 b , cpu 226 is configured to control device 122 . for example , cpu 226 is adapted to receive position information from the optical sensor , and is enabled to report the position information , optionally in a summarized fashion , using wireless logic 224 to communicate over wireless interconnect 114 . in various embodiments , cpu 226 includes two or more specialized controllers or cpus , such as an input mechanism controller and one or more network controllers . in some embodiments , cpu 226 is coupled to memory ( mem ) 222 . according to various embodiments , memory 222 is enabled to store one or more of : files resident on device 122 ; code to be executed by cpu 226 ; control and / or configuration information for device 122 ; data , such as packets , being sent to or from cellular interconnect 128 ; data , such as packets , being sent to or from wireless interconnect 114 ; and other data and / or code for controlling and / or operating device 122 . in some embodiments , memory 222 is coupled to one or more of cellular logic 228 and wireless logic 224 . in further embodiments device 122 includes a direct memory access ( dma ) function , and one or more of cellular logic 228 and wireless logic 224 are enabled to transfer data to memory 222 without cpu 226 moving the data . according to various embodiments , memory 222 includes any type or combination of types of memory that is able to be interfaced to cpu 226 , such as static random access memory ( sram ), dynamic random access memory ( dram ), programmable read - only memory ( prom ), electrically erasable programmable read - only memory ( eeprom ), or flash memory . in the illustrative embodiment of fig2 b , button 132 is coupled to cpu 226 . cpu 226 is enabled to detect on and / or off indications of button 132 ( or similar indications from other input mechanisms of device 122 ), and to optionally and / or selectably report the indications via wireless logic 224 . in some embodiments , whether and / or how the indications are reported via wireless logic 224 is dependent on an operating mode and / or on configuration , such as user configuration , of device 122 . in some embodiments , components of device 122 , such as cellular logic 228 and wireless logic 224 are incorporated on one or more printed circuit boards mounted inside device 122 . in various embodiments , some or all of the components are mounted on sensor printed circuit board 240 . many ways of physically organizing and coupling the components are possible within the scope of the techniques taught herein . in some embodiments , wireless logic 224 and chip 242 are both mounted on sensor printed circuit board 240 , and chip 242 is directly coupled to wireless logic 224 to report position information without intervention of cpu 226 . in these embodiments , cpu 226 is used to initialize and for exceptions related to chip 242 , and is not involved in the direct reporting of position information . in other embodiments , cpu 226 acts as an intermediary between chip 242 and wireless logic 224 . additionally , cpu 226 is enabled to process , such as by translating and / or summarizing and / or performing a protocol conversion , the position information determined by chip 242 prior to reporting the position information via wireless logic 224 . in various embodiments , cpu 226 is enabled to receive control information , such as commands , via wireless logic 224 , and to use the control information to control operation of chip 242 . for example , in response to a command received from a computer ( such as computer 110 as illustrated in fig1 ) via wireless logic 224 , cpu 226 is enabled to control the accuracy and / or the sensitivity of chip 242 . in some embodiments , cpu 226 is enabled to control power modes of chip 242 , either independently , or in response to control information received via wireless logic 224 . according to various embodiments , the power modes include a normal mode , a low power mode , a sleep mode , and a hibernate mode . fig2 c illustrates selected details of an offset top view of an illustrative embodiment of a device operable as a cellular communication device and as a wireless pointing device , and including multiple input mechanisms . according to various embodiments , device 123 is the same as one or more of device 120 ( as illustrated in fig1 ), device 121 ( as illustrated in fig2 a ), and device 122 ( as illustrated in fig2 b ). according to various embodiments , device 123 includes one or more of the illustrated input and / or output mechanisms : button 132 , screen 260 , left button 262 , wheel 264 , right button 266 . screen 260 is used as a display ( an output mechanism ). in some embodiments , screen 260 is a touch - sensitive screen and is one of the input mechanisms . other input and / or output mechanisms are compatible with the techniques taught herein . for example , in further embodiments , device 123 includes an audio output mechanism , such as a speaker , and an audio input mechanism , such as a microphone . in some embodiments , and when being used as a pointing device , left button 262 and right button 266 are configured to operate as a left mouse button and a right mouse button , such as for a two - button mouse . in further embodiments , wheel 264 is configured to operate as a middle mouse button and / or as a mouse wheel . many ways of organizing , arranging and specifying the function of the input and / or output mechanisms are possible within the scope of the techniques taught herein . any or all of the input mechanisms are optionally , according to various embodiments , programmable to affect operation of device 123 in one or more ways . for example , in some embodiments , left button 262 is programmable to operate as a left mouse button in a pointer mode , and as a “ pick - up call ” button in a communications mode . fig2 c also illustrates motion of device 123 , such as motion 180 of device 120 as illustrated in fig1 . the motion of device 123 has an x axis component ( x motion 282 ) and a perpendicular y axis component ( y motion 284 ). of course , the particular arrangement of the x and y axes illustrated in fig3 is arbitrary , and , for example , the x and y axes could be swapped , or the x and y axes could be rotated . similarly , in other embodiments , the coordinate system used is polar , rather than rectangular . when device 123 is moved , such as by sliding device 123 on a tracking surface ( such as tracking surface 282 as illustrated in fig2 b ), the motion of device 123 is detected by a sensor ( such as described with reference to fig2 b ). the sensor is enabled to report one or more components of the motion ( such as an x component represented by x motion 282 and a y component represented by y motion 284 ). in some embodiments , the motion of device 123 is reported as a relative ( to a previous position of device 123 ) movement in the x and / or y axes . fig3 illustrates selected details of a process used in an illustrative embodiment with a device , such as device 120 of fig1 , operable as a cellular communication device and as a wireless pointing device . process 300 starts (“ start ,” 302 ), for example , when the device is operated as a wireless pointing device , such as when a user changes an operating mode of the device to use the device as a wireless pointing device . process 300 includes multiple elements , and according to various embodiments , the elements are performed serially , in parallel , or in any combination of serially and in parallel . the linear flow of the multiple elements in fig3 is merely illustrative . furthermore , according to various embodiments , the device is able to perform other processes or operations during operation of process 300 . as a few of many examples of operations that , according to various embodiments , are performed during the operation of process 300 : initiating a telephone call ; receiving a telephone call ; participating in a telephone call ; indicating a reminder ( such as a calendar reminder ); receiving a text message ; and other operations performed by a cellular communication device , a pda , a pager , or another communication device . in process 300 , the device is enabled to track movement of the device (“ track movement ,” 310 ), such as with a motion sensor ( for example , optical sensor 241 as illustrated in fig2 b ). tracking the movement enables determining position information of the device (“ determine position ,” 320 ). in some embodiments , the position information is relative position information ( as explained with regard to fig2 c ). the position information is reported (“ report position ,” 330 ), such as over a wireless interconnect ( for example , wireless interconnect 114 as illustrated in fig1 ). reporting the position information includes the device sending the position information over the wireless interconnect , and another entity , such as computer 110 as illustrated in fig1 , receiving the position information from the wireless interconnect . in some embodiments , reporting the position information also reports indications of input mechanisms of the device , such as pressing or releasing of selected buttons , movement of scroll wheels , or input provided on a touch screen . the reported position information is used , at least in part , to control operation of the other entity (“ control operation ,” 340 ). for example , in some embodiments , the reported position information is used to control a graphical icon , such as a cursor , on a display of computer 110 , or to control operation of an application on computer 110 . process 300 continues (“ more ?” 350 ), repeating the “ track movement ” 310 , “ determine position ” 320 , “ report position ” 330 , and “ control operation ” 340 elements , as long as the device is operated as a wireless pointing device . for example , in some embodiments , process 300 ends (“ end ,” 360 ) when a user changes an operating mode of the device . fig4 illustrates an example of operating modes of a device , such as device 120 of fig1 , operable as a cellular communication device and as a wireless pointing device . as illustrated in the example of fig4 , the space of all device operating modes 400 of the device includes three primary operating modes represented as circles : cellular communication device mode 412 , wireless pointing device mode 414 , and file transfer mode 416 . the primary operating modes are illustrated as creating overlapping regions where more than one primary operating mode is active ( such as region 424 ), and non - overlapping regions where only a single primary operating mode is active ( such as region 420 ). outside of any of the primary operating modes is a “ no - mode ” region 499 where none of the primary operating modes are active . for example , no - mode region 499 , in some embodiments , corresponds to a “ flight mode ” where all communication modes are disabled . according to various embodiments , a default operating mode of the device is one or more of : an operating mode corresponding to region 420 ; an operating mode corresponding to another one of the regions ; and an operating mode selectable by a user of the device , such as via a menu on a screen of the device . according to various embodiments , a current operating mode of the device is one or more of : selectable by a user of the device , such as via a menu on a screen of the device , or via an input mechanism of the device ( such as a button ); changeable due to external events , such as the arrival of a telephone call or an initiation of a file transfer to the device by a computer or a device communicating over a wireless interconnect ; and changeable due to internal events , such as alarms , timers , or battery indications . when the device is operating in an operating mode corresponding to region 420 , the device is operable as a cellular communication device , and is not operable as a wireless pointing device or enabled to transfer files . when the device is operating in an operating mode corresponding to region 440 , the device is operable as a wireless pointing device , and is not operable as a cellular communication device or enabled to transfer files . when the device is operating in an operating mode corresponding to region 460 , the device is operable for file transfer , and is not operable as a cellular communication device or as a wireless pointing device . when the device is operating in an operating mode corresponding to region 424 , the device is operable as a cellular communication device and as a wireless pointing device , and is not enabled to transfer files . when the device is operating in an operating mode corresponding to region 426 , the device is operable as a cellular communication device and for file transfer , and is not operable as a wireless pointing device . in some embodiments , the device optionally and / or selectably has additional capabilities and / or functions in one or more of the operating modes . for example , in some embodiments , when operating in an operating mode corresponding to region 424 , device 120 as illustrated in fig1 has additional capabilities . arrival of a telephone call is enabled to send a “ pause ” command over wireless interconnect 114 , thus pausing operation of an application ( such as a gaming application ). in further embodiments , the pause command is sent automatically . in other embodiments , a user of the device is notified of the phone call , and the pause command is sent under control of the user , such as by activating an input mechanism of the device . in various embodiments , accepting the call changes the operating mode of the device . continuing the example , an input mechanism of the device is enabled to cause a “ resume ” command to be sent over wireless interconnect 114 ( in response to a user activating the input mechanism ) when the telephone call is completed ( or when the user decides not to accept the call ). in various embodiments , sending the “ resume ” command changes the operating mode of the device . the example of fig4 does not illustrate an operating mode in which the device is operable as both a wireless pointing device and for file transfer . such an operating mode is not precluded , it is just not illustrated in the example of fig4 . of course , according to various embodiments , other operating modes and other arrangements of operating modes are used . for example , in various embodiments , the device has operating modes including one or more of : cellular communication device mode , wireless pointing device mode , file transfer mode , web browsing mode , pager mode , game - playing mode , mp3 - playing mode , camera mode , tv - watching mode , and other operating modes of use in cellular telephones , pdas , pagers , communication devices , and other portable devices . any of the operating modes is , according to various embodiments , enabled to operate at a same time as any others of the operating modes . according to various embodiments , selection of one or more current operating modes of the device , features of operation in the operating modes , and functions of the input mechanisms of the device in the operating modes are all selectable by a user of the device , such as via a menu displayed on a screen of the device . one of skill in the art will recognize that the concepts taught herein can be tailored to a particular application in many other advantageous ways . in particular , those skilled in the art will recognize that the illustrated embodiments are but some of many alternative implementations that will become apparent upon reading this specification . the preceding embodiments are exemplary and not restrictive . although the specification may refer to “ an ”, “ one ”, “ another ”, or “ some ” embodiment ( s ) in several locations , this does not necessarily mean that each such reference is to the same embodiment ( s ), or that any features described apply only to specific embodiments .