Iconic Representation

Example Icons 

Sign out (photo taken at Lab1, FCSHD)

Sign out is indicate that user can use this door to go out through this door as well as it shows right direction for the user. 

Similar Icons

Photo taken at Cempaka College

No smoking sign shows that user is not allowed to smoke in certain area. It is much easier to understand using this symbol as it clearly 

 Symbolic Icons

On/off button on laptop. (photo taken at home)

Button on and off on the laptop is a symbolic icons as user knows function of that button because it similar with the other laptop. 

Arbitrary Icons

Sign at box of mineral water. (photo taken at home)

Sign of umbrella on the box has no relation with the mineral water and action that could be taken from user thus it shows that it is example of arbitrary icons.