A sign can be anything that signified something other than itself.

Three key ideas in semiotic:

i. Signifier is referring to the concept.

ii. Signified is referring to the object.

iii. Referent is referring to the particular instance of concept indicated by the signified.

Iconic refers to the image that contains an abstract symbol. The meaning of the image is derived long ago. For example, hibiscus flower is a icon for Malaysia.

Indexical refers to the image that contains an abstract symbol. The meaning of the image is derived long ago. For example, hibiscus flower is a symbol for Malaysia.

With hypermedia, icons are used on the web as a visual clue, instead of colour.

Animation can be defined as a set of images that can change over a period of time.

The main purpose of using icons is to show changes over a period of time. It can also act as a feedback to the user, indicating that their request is in progress.