“…The information visualizer (1991) was a 3D version of the Rooms virtual desktop (Henderson and Card, 1986) that also (besides the Perspective wall presented in 4.4) allowed users to visualise their information in a 3D hierarchical visualisation Cone Tree with a zooming interface . Several other tree based visualisation techniques (whether used for PIM or not) to visualise large hierarchies are available such as a classic radial tree, Fractal trees (1993) (Koike and Yoshihara, 1993), Fviz (1995) -an improved cone tree or a balloon view of a radial tree (Carriere and Kazman, 1995), Hyperbolic browser (1995) (later Star Tree Studio) -a hyperbolic tree with a fisheye zooming capability (Lamping et al, 1995), RF-Cone tree (1997) -a 3D version of a tree similar to Fviz (Teraoka and Maruyama, 1997), Cata-Cone tree (1997) -a cone tree with additional tree information (Hearst and Karadi, 1997), Disc Trees (1998) -another 3D variant of a cone like tree (Jeong and Pang, 1998), Circular trees (2006) -similar to radial or hyperbolic tree (Ciccarelli et al, 2006), Hierarchical Edge Bundles (2006) (Holten, 2006), and Bubble tree (2006) (Grivet et al, 2006). There are also more abstract hierarchy visualisations such as Botanical Trees Tree Viewer (2001) (Kleiberg et al, 2001; and PhylloTrees (2006) (Neumann et al, 2006).…”