Image Maps
Here is a common form for representing the three activities in a triathlon.
The first icon represents swimming, the second represents cycling and the third
represents running. Note that the default for the full shape is active under the
running man and in the perimeter of the overall image.
Note that the shape of the PHP book is a five-sided polygon.
The above examples come from need to Adam Freeman in "The Definitive Guide to HTML5" and
Zak Ruvalcaba and Anne Boehm in "Murach's HTML5 and CSS3" respectively.