Many computing scenarios involve the presentation of many related items in an item set, such as the components of a software architecture, devices communicating over a network, and related elements in a relational database. Where the associations between items are undirected (e.g., a peer relationship between two computers on a: network), the item set may comprise an undirected graph. Alternatively, some or all of the associations are directed, such as a superior/subordinate relationship between two items (e.g., a server/client relationship between two computers on a network), and the item set may comprise a partly or wholly directed graph. The items may be presented to a user, such as in a software architecture diagram, a network map, and a visual relational database schema. The presentation of such items may facilitate the user in exploring various aspects of the item set, such as the types of items contained therein, the relationships thereamong, and the hierarchy established by the directed relationships among items.