A relation defines a relationship which has its origin in the set of source objects. The objects affected by that relationship are the destination objects. The type of the relationship is defined by the set of describing objects. Note that objects may appear in either set, which means that bidirectional relationships are possible as well. Relations are discussed in more depth in Section 4.7 .
Scenes are equivalent to scenes in movies.
They are the frame, within which the story is told. Scenes hold the description of what, when and where things happen. These sequences are defined by paths See Section 4.8 for further discussion. A story is told by objects, which appear on the stage. The sequence of these events comprises the story.