Techniques for visualizing sets are described. Arbitrary subsets of data elements are represented by corresponding graphic lines. The data elements in a set are connected up sequentially by a corresponding graphic line, the graphic line passing through each data element once with minimal or no self-overlapping. The graphic lines may be curved, for instance in the form of spline segments interconnecting nodes that represent the respective subsets. Each line may have a different color. Data elements not belonging to a subset may still be represented by a nodes but are not connected with any of the graphic lines, thus it can be seen which data elements belong to which sets, if any.