Thank you! Someone just forked the notebook, adding satellite texturing — that's a really cool aspect of Observable (and I'll probably merge it back): https://observablehq.com/@rzoller/martin-real-time-rtin-terr...
The non-textured demo actually looks better. Nothing that can't be fixed by stitching higher resolution sat imagery though!
https://blog.mapbox.com/bringing-3d-terrain-to-the-browser-w...
Is it just faster? Also, is Peter's work FOSS?