A composition is an existence dependency between the composite object and its parts. One part can only be contained in at most one composite object at one specific point in time. Multiplicity at aggregating end is at maximum 1, the composite objects form a tree.
If the composite object is deleted, its parts are also deleted. Syntax: solid diamond at the aggregating end.
For example, a Beamer is part of LectureHall which is part of Building.
