With great help of @Lao here is my first visualization with the new notebook 2.0. I truly enjoyed it - especially @Lao chiming in 
- gave me the community vibes back. I will post my experience and some suggestions in a separate post soon.
https://observablehq.com/@ambassadors/hyperbolic-tree-viewer-part-3
I love how the points get smaller near the edge and how your geodesic links work. Both really help me understand the hyperbolic geometry.
Have you tried any other hyperbolic projects other than the Poincaré disk? (Stereographic, gnomic, orthographic, azimuthal equidistant, ect). Just like globe projections, I’m sure there is a whole world of hyperbolic projections that people aren’t familiar with because it isn’t a common medium. For example, I wonder if a Tidy Tree or Custer Tree could be graphed on the Poincaré half-plane projection, so left/right drills down and up, and up/down scrolls on that hierarchy level.
What is the best way for me to cite your notebooks so attention is consolidated to the most recent? Do you plan on merging any of these changes back to part 1?