A Venn diagram may also be called a primary diagram, set diagram or logic diagram. It is a diagram that shows "all" possible logical relations between a finite collection of different sets. These diagrams depict elements as points in the plane, and sets as regions inside closed curves. A Venn diagram consists of multiple overlapping closed curves, usually circles, each representing a set. The points inside a curve labelled "S" represent elements of the set "S", while points outside the boundary represent elements not in the set "S". This lends itself to intuitive visualizations; for example, the set of all elements that are members of both sets "S" and "T", denoted "S" ∩ "T" and read "the intersection of "S" and "T"", is represented visually by the area of overlap of the regions "S" and "T".