Semiotics can be divided into three main groups, depending on what they semiotics are used for and what they show/ These groups are:
An Icon is an image used to represent an object that physically resembles the object in question. The image must resemble it closely; in the case of a weapon, for example, a handgun image cannot be used for a shotgun. That would be a symbol, as the image does not closely resemble the object you will get. Examples include more or less any item from Minecraft and coins from the Mario series of games. In the Minecraft example, the images shown in the inventory system and in the environment closely resemble the item you will actually get by picking them up. The Mario example is also an example of an icon, because picking up a coin in game will give you a coin in game.
An Index is a sensory input, such as visual or auditory data, that signals the arrival of something. These are generally used for threats, as all animals are naturally responsive to some indexical triggers. Lower animals have innate, inbuilt indexical triggers, while higher animals have both innate and learned indexical triggers. Examples are red lights while on the road, and the sound a van makes while it is reversing. The red lights are illuminated when the vehicle begins reversing, and the noise begins playing, so pedestrians associate the lights and sound with a reversing vehicle and know that they are in danger. Another example would be the sounds made by hostile entities in Minecraft; the noises are only made when the entity is in striking distance, so hearing them means that the player is in danger.
A symbol is an image used to represent a resource or item that does not resemble the resulting resource or item. These often evolve over time, such as the use of arrows for indication of direction and the ‘love heart’ shape, which is often used for love in real life and for health in computer games. A symbol does not look like what it represents; if it does, it is an icon, not a symbol. Examples are everywhere, such as arrows on road signs or data on a game’s HUD. The arrows do not look like where they actually point to, allowing them to be used in generic situations. Most icons are generic, which is one reason why they are used: they can be applied in many situations to mean the same thing, in the reasonable faith that the viewer/player will know what the icons mean quickly. Examples are arrows, or the play/pause/record symbols used on media players and devices. As these symbols are standards throughout the industry, they are easily recognisable to most people. The icons from the HUD, such as the example from Fallout below, are often more like what they represent, but are still visually different; for example, the icon shown is for a weapons upgrade, not a Kalashnikov rifle. Symbols are learned; the symbols we use must be taught to us, usually as children, before we can make sense of them.