In computing, a mouse (plural mice or mouses) functions as a pointing device by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of a small case, held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features can add more control or dimensional input. The mouse's motion typically translates into the motion of a pointer on a display.
The name mouse, coined at the Stanford Research Institute, derives from the resemblance of early models (which had a cord attached to the rear part of the device, suggesting the idea of a tail) to the common eponymous rodent.
The first marketed integrated mouse — shipped as a part of a computer and intended for personal computer navigation — came with the Xerox 8010 Star Information System in 1981.

Technologies
Douglas Engelbart of the Stanford Research Institute invented the mouse in 1963


Early mice
Bill English, builder of Engelbart's original mouse,

Mechanical mice
An optical mouse uses a light-emitting diode and photodiodes to detect movement relative to the underlying surface, rather than moving some of its parts — as in a mechanical mouse.
Early optical mice, circa 1980, came in two different varieties:
These two mouse types had very different behaviors, as the Kirsch mouse used an x-y coordinate system embedded in the pad, and would not work correctly when rotated, while the Lyon mouse used the x-y coordinate system of the mouse body, as mechanical mice do.
As computing power grew cheaper, it became possible to embed more powerful special-purpose image-processing chips in the mouse itself. This advance enabled the mouse to detect relative motion on a wide variety of surfaces, translating the movement of the mouse into the movement of the pointer and eliminating the need for a special mouse-pad. This advance paved the way for widespread adoption of optical mice.
Modern surface-independent optical mice work by using an optoelectronic sensor to take successive pictures of the surface on which the mouse operates. Most of these mice use LEDs to illuminate the surface that they track over; marketers often mislabel these LED optical mice as laser mice, confusing them with true laser mice. Changes between one frame and the next are processed by the image processing part of the chip and translated into movement on the two axes using an optical flow estimation algorithm. For example, the Avago Technologies ADNS-2610 optical mouse sensor processes 1512 frames per second: each frame consisting of a rectangular array of 18×18 pixels, and each pixel can sense 64 different levels of gray. Laser mice
Optical mice have no rolling parts, and therefore (unlike mechanical mice, which can clog up with lint) they do not normally require maintenance other than removing debris that might collect under the light-emitter. However, they generally cannot track on glossy and transparent surfaces, including some mouse-pads, sometimes causing the cursor to drift unpredictably during operation. Mice with less image-processing power also have problems tracking fast movement, though high-end mice can track at 2 m/s (80 inches per second) and faster.
Proponents note that some models of laser mice can track on glossy and transparent surfaces, and have a much higher sensitivity than either their mechanical or optical counterparts. Such models of laser mice cost more than both their LED based counterparts and mechanical mice.
As of 2006, mechanical mice have lower average power demands than their optical counterparts. This typically has no practical impact for users of cabled mice (except possibly those used with battery-powered computers, such as notebook models), but has an impact on battery-powered wireless models.
Optical models will outperform mechanical mice on uneven, slick, squishy, sticky or loose surfaces, and generally in mobile situations lacking mouse pads. Since optical mice render movement based on an image which the LED illuminates, use with multi-colored mousepads may result in unreliable performance, however, laser mice do not suffer these problems and will track on such surfaces. The advent of affordable high-speed, low-resolution cameras and the integrated logic in optical mice provides an ideal laboratory for experimentation on next-generation input-devices. Experimenters can obtain low-cost components simply by taking apart a working mouse and changing the optics or by writing new software.

Optical versus mechanical mice
Inertial mice use a tuning fork or other accelerometer (US Patent 4787051) to detect movement for every axis supported. Usually cordless, they often have a switch to deactivate the movement circuitry between use, allowing the user freedom of movement without affecting the pointer position. A patent for an inertial mouse claims that such mice consume less power than optically based mice, offer an increased level of sensitivity, and reduced weight and increased ease-of-use.

Inertial mice
Also known as flying mice, bats, or wands, these devices generally function through ultrasound. Probably the best known example would be 3DConnexion/Logitech's SpaceMouse from the early 1990s.
In the late 1990s Kantek introduced the 3D RingMouse. This wireless mouse was worn on a ring around a finger, which enabled the thumb to access three buttons. The mouse was tracked in three dimensions by a base station. Despite a certain appeal, it was finally discontinued because it did not provide sufficient resolution.
A recent consumer 3D pointing device is the Wii Remote. While primarily a motion-sensing device (that is, it can tell which way it's going and which way it's tilted), Wii Remote can also detect its spatial position by comparing the distance and position of the lights from the IR emitter using its integrated IR camera (since the nunchuk lacks a camera, it can only tell its current heading and orientation). The obvious drawback to this approach is that it can only produce spatial coordinates while its camera can see the sensor bar.

3D mice
Double mouse allow for two mice to be used by both hands as input devices such as when operating various graphics and multimedia applications.

Double mouse
To transmit their input, typical cabled mice use a thin electrical cord terminating in a standard connector, such as RS-232C, PS/2, ADB or USB. Cordless mice instead transmit data via infrared radiation (see IrDA) or radio (including Bluetooth or WiFi), although many such cordless interfaces are themselves connected through the aforementioned wired serial busses.
While the electrical interface and the format of the data transmitted by commonly available mice is currently standardized on USB, in the past it varied between different manufacturers.

Connectivity and communication protocols
Standard PC mice once used the RS-232C serial standard (released in 1969), via a DB-9 connector. The Mouse Systems Corporation version used a five-byte protocol and supported three buttons. The Microsoft version used an incompatible three-byte protocol and only allowed for two buttons. Due to the incompatibility, some manufacturers sold serial mice with a mode switch: "PC" for MSC mode, "MS" for Microsoft mode.

Serial interface and protocol

For more details on this topic, see PS/2 connector. PS/2 interface and protocol
A Microsoft IntelliMouse relies on an extension of the PS/2 protocol: the ImPS/2 or IMPS/2 protocol (the abbreviation combines the concepts of "IntelliMouse" and "PS/2"). It initially operates in standard PS/2 format, for backwards compatibility. After the host sends a special command sequence, it switches to an extended format in which a fourth byte carries information about wheel movements. The IntelliMouse Explorer works analogously, with the difference that its 4-byte packets also allow for two additional buttons (for a total of five).
Mouse-vendors also use other extended formats, often without providing public documentation.
For 3D or 6DOF input, vendors have made many extensions both to the hardware and to software. In the late 90's Logitech created ultrasound based tracking which gave 3D input to a few millimeters accuracy, which worked well as an input device but failed as a money making product.

Extensions: IntelliMouse and others
In 1986 Apple first implemented the Apple Desktop Bus allowing the daisy-chaining together of up to 16 devices, including arbitrarily many mice and other devices on the same bus with no configuration whatsoever. Featuring only a single data pin, the bus used a purely polled approach to computer/mouse communications and survived as the standard on mainstream models (including a number of non-Apple workstations) until 1998 when iMac began the industry-wide switch to using USB. Beginning with the "Bronze Keyboard" PowerBook G3 in May 1999, Apple dropped the external ADB port in favor of USB, but retained an internal ADB connection in the PowerBook G4 for communication with its built-in keyboard and trackpad until early 2005.

Apple Desktop Bus
In 2000, Logitech introduced the "tactile mouse", which contained a small actuator that made the mouse vibrate. Such a mouse can augment user-interfaces with haptic feedback, such as giving feedback when crossing a window boundary.
Other unusual variants have included a mouse that a user holds freely in the hand, rather than on a flat surface, and that detects six dimensions of motion (the three spatial dimensions, plus rotation on three axes). Its vendor marketed it for business presentations in which the speaker stands or walks around. So far, these mice have not achieved widespread popularity.

Tactile mice
In contrast to the motion-sensing mechanism, the mouse's buttons have changed little over the years, varying mostly in shape, number, and placement. Engelbart's very first mouse had a single button; Xerox PARC soon designed a three-button model, but reduced the count to two for Xerox products. After experimenting with 4-button prototypes Apple reduced it back to one button with the Macintosh in 1984, while Unix workstations from Sun and others used three buttons. OEM bundled mice usually have between one and three buttons, although in the aftermarket many mice have always had five or more.
The three-button scrollmouse has become the most commonly available design. As of 2007 (and roughly since the late 1990s), users most commonly employ the second button to invoke a contextual menu in the computer's software user interface, which contains options specifically tailored to the interface element over which the mouse pointer currently sits. By default, the primary mouse button sits located on the left-hand side of the mouse, for the benefit of right-handed users; left-handed users can usually reverse this configuration via software.
On systems with three-button mice, pressing the center button (a middle click) typically opens a system-wide noncontextual menu. In the X Window System, middle-clicking by default pastes the contents of the primary buffer at the pointer's position. Many users of two-button mice emulate a three-button mouse by clicking both the right and left buttons simultaneously.

Buttons
Aftermarket manufacturers have long built mice with five or more buttons. Depending on the user's preferences and software environment, the extra buttons may allow forward and backward web-navigation, scrolling through a browser's history, or other functions, including mouse related functions like quick-changing the mouse's resolution/sensitivity. As with similar features in keyboards, however, not all software supports these functions. The additional buttons become especially useful in computer games, where quick and easy access to a wide variety of functions (for example, weapon-switching in first-person shooters) can give a player an advantage. Because software can map mouse-buttons to virtually any function, keystroke, application or switch, extra buttons can make working with such a mouse more efficient and easier.
In the matter of the number of buttons, Douglas Engelbart favored the view "as many as possible". The prototype that popularised the idea of three buttons as standard had that number only because "we could not find anywhere to fit any more switches".

Additional buttons
The scroll wheel, a notably different form of mouse-button, consists of a small wheel that the user can rotate to provide immediate one-dimensional input. Usually, this input translates into "scrolling" up or down within the active window or GUI-element . The scroll wheel can provide convenience, especially when navigating a long document. The scroll wheel nearly always includes a third (center) button. Under many Microsoft Windows applications, appropriate pressure on the wheel activates autoscrolling, and in conjunction with the control key (Ctrl) may give the capability of zooming in and out; applications that support this feature include Adobe Reader, Microsoft Word, Internet Explorer, Opera, Mozilla Firefox and Mulberry. Some applications also allow the user to scroll left and right by pressing the shift key while using the mouse wheel.
Note that scrollwheels almost always function more as two switches, rotating only in discrete "clicks" rather than actually acting as a third analog axis.
Manufacturers may refer to scroll-wheels by different names for branding purposes; Genius, for example, usually brand their scroll-wheel-equipped products "Netscroll".
Mouse Systems introduced the scroll-wheel commercially in 1995, envisioned to be used for scrolling, zooming or (with appropriate software) controlling a second mouse cursor.

Wheels

Rollover
Drag
Click

• (left) Single-click
  (left) Double-click
  (left) Triple-click
  Right-click
  Rocker
  
  
  
  • Combination of right-click then left-click or keyboard letter
    Combination of left-click then right-click or keyboard letter
    Combination of left or right-click and the mouse wheel Button techniques
    
    Select
    Launch (an application)
    Cut
    Paste
    Drag and drop Common button operations
    The computer-industry often measures mouse sensitivity in terms of counts per inch (CPI), commonly expressed less correctly as dots per inch (DPI) — the number of steps the mouse will report when it moves one inch. In early mice, this specification was called pulses per inch (ppi). If the default mouse-tracking condition involves moving the pointer by one screen-pixel or dot on-screen per reported step, then the CPI does equate to DPI: dots of pointer motion per inch of mouse motion. The CPI or DPI as reported by manufacturers depends on how they make the mouse; the higher the CPI, the faster the pointer moves with mouse movement. However, software can adjust the mouse sensitivity, making the cursor move faster or slower than its DPI. Current software can change the speed of the pointer dynamically, taking into account the mouse's absolute speed and the movement from the last stop-point. Different software may name the settings "acceleration" or "speed" — referring respectively to "threshold" and "pointer precision".
    For simple software, when the mouse starts to move, the software will count the number of "counts" received from the mouse and will move the pointer across the screen by that number of pixels (or multiplied by a factor f1=1,2,3). So, the pointer will move slowly on the screen, having a good precision. When the movement of the mouse reaches the value set for "threshold", the software will start to move the pointer more quickly; thus for each number n of counts received from the mouse, the pointer may move (f2 x n) pixels, where f2=2,3...10. Usually, the user can set the value of f2 by changing the "acceleration" setting.
    Operating systems sometimes apply acceleration, referred to as "ballistics", to the motion reported by the mouse. For example, versions of Windows prior to Windows XP doubled reported values above a configurable threshold, and then optionally doubled them again above a second configurable threshold. These doublings applied separately in the X and Y directions, resulting in very nonlinear response. For example one can see how the things work in Microsoft Windows NT. Starting with Windows XP OS version of Microsoft and many OS versions for Apple Macintosh, computers use a smoother ballistics calculation that compensates for screen-resolution and has better linearity.
    
    Mouse speed
    The first known publication of the word "mouse" is in Bill English's 1965 publication "Computer-Aided Display Control"
    The Compact Oxford English Dictionary (third edition) and the fourth edition of The American Heritage Dictionary of the English Language endorse both computer mice and computer mouses as correct plural forms for computer mouse. The form mice, however, appears most commonly, while some authors of technical documents may prefer either mouse devices or the more generic pointing devices. The plural mouses treats mouse as a "headless noun."
    
    Etymology
    
    Accessories
    
    
    Main article: Mousepad Mousepad
    Mouse foot-covers (or foot-pads) consists of low-friction or polished plastic. This makes the mouse glide with less resistance over a surface. Some higher quality models have teflon feet to reduce friction even further.
    
    Foot covers
    Around 1981 Xerox included mice with its Xerox Star, based on the mouse used in the 1970s on the Alto computer at Xerox PARC. Sun Microsystems, Symbolics, Lisp Machines Inc., and Tektronix also shipped workstations with mice, starting in about 1981. Later, inspired by the Star, Apple Computer released the Apple Lisa, which also used a mouse. However, none of these products achieved large-scale success. Only with the release of the Apple Macintosh in 1984 did the mouse see widespread use.
    The Macintosh design, commercially successful and technically influential, led many other vendors to begin producing mice or including them with their other computer products. The widespread adoption of graphical user interfaces in the software of the 1980s and 1990s made mice all but indispensable for controlling computers.
    
    Mice in the marketplace
    
    Trackball – the user rolls a ball mounted in a fixed base.
    Touchpad – detects finger movement about a sensitive surface — the norm for modern laptop computers. At least one physical button normally comes with the touchpad, but users can also (configurably) generate a click by tapping on the pad. Advanced features include detection of finger pressure, and scrolling by moving one's finger along an edge.
    Pointing stick – a pressure sensitive nub used like a joystick on laptops, usually found between the g, h, and b keys on the keyboard.
    Consumer touchscreen devices exist that resemble monitor shields. Framed around the monitor, they use software-calibration to match screen and cursor positions. Many firms that integrate touchscreen equipment into existing displays and all-in-one devices (such as portables PCs) for a reasonable fee are also in operation.
    Mini-mouse – a small egg-sized mouse for use with laptop computers — usually small enough for use on a free area of the laptop body itself.
    Camera mouse – a camera tracks a user's head-movement and moves the onscreen cursor. Natural pointers track the dot on a person's head and move the cursor accordingly. See also EagleEyes
    Palm mouse – held in the palm and operated with only two buttons; the movements across the screen correspond to a feather touch, and pressure increases the speed of movement.
    Footmouse – a mouse variant for those who do not wish to or cannot use the hands (see carpal tunnel) or the head; instead, it provides footclicks.
    Graphics tablet – a tablet with a pen or stylus used for pointing. The user holds the device like a normal pen and moves it across a special pad. The thumb usually controls the clicking via a two-way button on the top of the pen, or by tapping.
    Similar to a mouse is a puck, in which rather than tracking the speed of the device, it tracks the absolute position of a point on the device (typically a set of crosshairs painted on a transparent plastic tab sticking out from the top of the puck). Pucks are typically used for tracing in CAD/CAM/CAE work, and are often accessories for larger graphics tablets.
    Eyeball-controlled – A mouse controlled by the user's eyeball/retina movements, allowing cursor-manipulation without touch.
    Finger-mouse – An extremely small mouse controlled by two fingers only; the user can hold it in any position
    Gyroscopic mouse - A gyroscope senses the movement of the mouse as it moves through the air. Users can operate a gyroscopic mouse when they have no room for a regular mouse or must give commands while standing up. This input device needs no cleaning and can have many extra buttons, in fact, some laptops doubling as TVs come with gyroscopic mice that resemble, and double as, remotes with LCD screens built in. Alternative pointing devices
    Computer-users usually utilize a mouse to control the motion of a cursor in two dimensions in a graphical user interface. Clicking or hovering can select files, programs or actions from a list of names, or (in graphical interfaces) through pictures called "icons" and other elements. For example, a text file might be represented by a picture of a paper notebook, and clicking while the pointer hovers this icon might cause a text editing program to open the file in a window. (See also point-and-click)
    Users can also employ mice gesturally; meaning that a stylized motion of the mouse cursor itself, called a "gesture", can issue a command or map to a specific action. For example, in a drawing program, moving the mouse in a rapid "x" motion over a shape might delete the shape.
    Gestural interfaces occur more rarely than plain pointing-and-clicking; and people often find them more difficult to use, because they require finer motor-control from the user. However, a few gestural conventions have become widespread, including the drag-and-drop gesture, in which:
    For example, a user might drag-and-drop a picture representing a file onto a picture of a trash-can, thus instructing the system to delete the file.
    Other uses of the mouse's input occur commonly in special application-domains. In interactive three-dimensional graphics, the mouse's motion often translates directly into changes in the virtual camera's orientation. For example, in the first-person shooter genre of games (see below), players usually employ the mouse to control the direction in which the virtual player's "head" faces: moving the mouse up will cause the player to look up, revealing the view above the player's head.
    When mice have more than one button, software may assign different functions to each button. Often, the primary (leftmost in a right-handed configuration) button on the mouse will select items, and the secondary (rightmost in a right-handed) button will bring up a menu of alternative actions applicable to that item. For example, on platforms with more than one button, the Mozilla web browser will follow a link in response to a primary button click, will bring up a contextual menu of alternative actions for that link in response to a secondary-button click, and will often open the link in a new tab or window in response to a click with the tertiary (middle) mouse button.
    
    The user presses the mouse button while the mouse cursor hovers over an interface object
    The user moves the cursor to a different location while holding the button down
    The user releases the mouse button Applications of mice in user-interfaces
    The issue of whether pack-in bundled mice "should" have exactly one button or more than one has attracted an enormous amount of controversy. From the first Macintosh until late 2005 (and all Apple portables still have 1-button pointers), Apple shipped every computer with a single-button mouse (and in fact never produced multibutton mice even as options until the current Mighty Mouse, with its predecessor often jocularly referred to as a "0-button mouse"), whereas most other platforms used multi-button mice. Apple and its advocates promoted single-button mice as more user-friendly, and portrayed multi-button mice as confusing for novice users. The Macintosh user interface, by design, always has and still does make all functions available with a single-button mouse. Apple's Human Interface Guidelines still specify that all software-providers need to make functions available with a single button mouse. However, X Window System applications, which Mac OS X can also run, have developed with the use of two-button or even three-button mice in mind, causing even simple operations like "cut and paste" to become awkward (although Apple's default X Window environment has built-in workarounds, just like their old wintel-on-a-card systems).
    While there has always been an aftermarket for mice with two, three, or more buttons among experienced Macintosh users and extensive configurable support to compliment such devices in all major software packages on the platform, Mac OS X shipped with hardcoded support for multi-button mice. On August 2, 2005, Apple introduced their Mighty Mouse multi-button mouse, which has four independently-programmable buttons and a trackball-like "scroll ball" which allows the user to scroll in any direction. Since the mouse uses touch-sensitive technology (rather than having visible divisions into separate buttons), users can treat it as a one-, two-, three-, or four-button mouse, as desired.
    Advocates of multiple-button mice argue that support for a single-button mouse often leads to clumsy workarounds in interfaces where a given object may have more than one appropriate action. One workaround was the double click, first used on the Apple Lisa, to allow both the "select" and "open" operation to be performed with a single button. Several common workarounds exist, and some are specified by the Apple Human Interface Guidelines.
    One such workaround (that favored on Apple platforms) has the user hold down one or more keys on the keyboard before pressing the mouse button (typically control on a Macintosh for contextual menus). This has the disadvantage that it requires that both the user's hands be engaged. It also requires that the user perform actions on completely separate devices in concert; that is, holding a key on the keyboard while pressing a button on the mouse. This can be a very daunting task for a disabled user (although Macs have shipped with "sticky keys" features in Easy Access for decades).
    Another involves the press-and-hold technique. In a press-and-hold, the user presses and holds the single button. After a certain period, software perceives the button press not as a single click but as a separate action. This has two drawbacks: first, a slow user may press-and-hold inadvertently. Second, the user must wait for the software to detect the click as a press-and-hold, otherwise the system might interpret the button-depression as a single click. Furthermore, the remedies for these two drawbacks conflict with each other: the longer the lag time, the more the user must wait; and the shorter the lag time, the more likely it becomes that some user will accidentally press-and-hold when meaning to click. Studies have found all of the above workarounds less usable than additional mouse buttons for experienced users.
    Alternatively, the user needs to hold down a key on the keyboard while pressing the button (Macintosh computers use the ctrl key). This has the disadvantage that it requires that both the user's hands be engaged. It also requires that the user perform two actions on completely separate devices in concert; that is, pressing a key on the keyboard while pressing a button on the mouse. This can be a very daunting task for a disabled user. Studies have found all of the above workarounds less usable than additional mouse buttons for experienced users.
    Most machines running Unix or a Unix-like operating system run the X Window System which almost always encourages a three-button mouse. X numbers the buttons by convention. This allows user instructions to apply to mice or pointing devices that do not use conventional button placement. For example, a left handed user may reverse the buttons, usually with a software setting. With non-conventional button placement, user directions that say "left mouse button" or "right mouse button" are confusing. The ground-breaking Xerox Parc Alto and Dorado computers from the mid-1970s used three-button mice, and each button was assigned a color. Red was used for the left (or primary) button, yellow for the middle (secondary), and blue for the right (meta or tertiary). This naming convention lives on in some SmallTalk environments, such as Squeak, and can be less confusing than the right, middle and left designations.
    Acorn's RISC OS based computers necessarily use all three mouse buttons throughout their WIMP based GUI. RISC OS refers to the three buttons (from left to right) as Select, Menu and Adjust. Select functions in the same way as the "Primary" mouse button in other operating systems. Menu will bring up a context-sensitive menu appropriate for the position of the mouse pointer, and this often provides the only means of activating this menu. This menu in most applications equates to the "Application Menu" found at the top of the screen in Mac OS, and underneath the window title under Microsoft Windows. Adjust serves for selecting multiple items in the "Filer" desktop, and for altering parameters of objects within applications — although its exact function usually depends on the programmer.
    
    One, two or three buttons?
    Mice often function as an interface for PC-based computer games and sometimes for video game consoles. They often appear in combination with the keyboard. In arguments over the best gaming platform, protagonists often cite the mouse as a possible advantage for the PC — depending on the gamer's personal preferences.
    
    Mice in gaming
    Due to the cursor-like nature of the crosshairs in shooter games, a combination of mouse and keyboard provides a popular way to play first-person shooter (FPS) games. Players use the X-axis of the mouse for looking (or turning) left and right, leaving the Y-axis for looking up and down. The left button usually controls primary fire. Many gamers prefer this over a gamepad or joystick because it allows them to aim quickly and accurately without auto-aim assist. If the game supports multiple fire-modes, the right button often provides secondary fire from the selected weapon. Secondary weapons include grenades, knives, etc. The right button may also provide bonus options for a particular weapon, such as allowing access to the scope of a sniper rifle or allowing the mounting of a bayonet or silencer or sometimes even jumping.
    Gamers can use a scroll wheel for changing weapons, or for controlling scope-zoom magnification. On most FPS games, programming may also assign more functions to additional buttons on mice with more than three controls. A keyboard usually controls movement (for example, WASD, for moving forward, left, backward and right, respectively) and other functions such as changing posture. Since the mouse serves for aiming, a mouse that tracks movement accurately and with less lag (latency) will give a player an advantage over players with less accurate or slower mice.
    An early technique of players, circle-strafing, saw a player continuously strafing while aiming and shooting at an opponent by walking in circle around the opponent with the opponent at the center of the circle. Players could achieve this by holding down a key for strafing while continuously aiming the mouse towards the opponent.
    Games using mouses for input have such a degree of popularity that many manufacturers, such as Logitech, and Razer USA Ltd, make peripherals such as mice and keyboards specifically for gaming. Such devices frequently feature (in the case of mice) adjustable weights, high-resolution optical or laser components, additional buttons, ergonomic shape, and other features such as adjustable DPI.
    
    First-person shooters
    Many games, such as first- or third-person shooters, have a setting named "invert mouse" or similar (not to be confused with "button inversion", sometimes performed by left-handed users) which allows the user to look downward by moving the mouse forward and upward by moving the mouse backward (the opposite of non-inverted movement). This control system resembles that of aircraft control sticks, where pulling back causes pitch up and pushing forward causes pitch down; computer joysticks also typically emulate this control-configuration.
    After id Software's Doom, the game that popularized FPS games but which did not support vertical aiming with a mouse (the y-axis served for forward/backward movement), competitor 3D Realms' Duke Nukem 3D became one of the first games that supported using the mouse to aim up and down. It and other games using the Build engine had an option to invert the Y-axis. The "invert" feature actually made the mouse behave in a manner that users now regard as non-inverted (by default, moving mouse forward resulted in looking down). Soon after, id Software released Quake, which introduced the invert feature as users now know it. Other games using the Quake engine have come on the market following this standard, likely due to the overall popularity of Quake.
    
    Invert mouse setting
    In the early 1990s the Super Nintendo Entertainment System video game system featured a mouse in addition to its controllers. The Mario Paint game in particular used the mouse's capabilities, as did its successor on the N64. Sony Computer Entertainment released an official mouse product for the PlayStation console, and included one along with the Linux for PlayStation 2 kit. However, users can attach virtually any USB mouse to the PlayStation 2 console.
    
    See also