Use this Four Circle Venn Diagram to demonstrate overlapping relationships or interconnected ideas or concepts. Excellent for establishing the relationships between four elements. A Venn diagram (also known as a primary diagram, set chart, or logic diagram) is a diagram that depicts all of the logical relationships that can exist between a finite collection of different sets. A Venn diagram comprises several overlapping closed curves, typically circles, representing a set. This circular diagram can also represent a continuous sequence of four stages, tasks, or events in a circular flow. It can also be used to demonstrate four ideas or concepts.