Iliad is based on standalone graphical objects called buildables. Buildables are stateful objects and know how to print themselves as HTML through elements. You will most of the time use two kind of buildables: widgets and applications.
Building methods and application controllers both answer other buildable objects, later printed as HTML sent to the client using elements.
These methods will most of the time answer either a widget or a block.
Default controller method of an application answering a counter widget.
This controller method answers a block taking an element as parameter.