To visualize the relationships between subsets of the universal set you can use Venn diagrams. To construct one, you should divide the plane into a number of cells using n figures. Each figure in the chart represents a single set of, and n is the number of represented sets. Splitting is done in a way that there is one and only one cell for any set of these figures, the points of which belong to all the figures from the set and do not belong to others. The plane on which the figures are represented, is the universal set U. Thus, the point which does not belong to any of the figures, belongs only to U.
