Critical Zones region where zoom-in brings interesting views show with navigation "residue" unambiguous action choice visible critical zone "residue" of stuff beneath zoom out if see nothing extension to VN theory 3. all views contain good residue of all nodes 4. all links must have small outlink-info must build support for these into ZUIs do not have "minsize", always use a few pixels they don't address clutter/scalability 26