A tree is rendered with nodes and edges but display space is subject to a particular curvature (hence the name) : more space is allocated to the focus node while the parent and children, still in the immediate visual context, appear slightly smaller. The grandparents and grandchildren are still visible but come out even smaller. As we move away from the focus node, less display space is allotted to the nodes, which gradually disappear towards the disk's border, as though the whole hierarchy were seen through a fisheye lens.