Might depend on what they've implemented so far. The simplex in figure 2 from the paper looks a lot like some of the simplex plots seen in Keenan Crane's work here:
https://www.cs.cmu.edu/~kmcrane/
And the authors have at least that connection to the ``Carnegie Mellon Geometry Collective,'' (see their prior work on his page) so I'd include discrete differential geometry in your list. This has connections (eh hem) all over...
Edit: For some reason I missed the Penrose site at the link and skipped straight to the PDF short introduction. I am presenting somewhat redundant information above. Sorry!
And the authors have at least that connection to the ``Carnegie Mellon Geometry Collective,'' (see their prior work on his page) so I'd include discrete differential geometry in your list. This has connections (eh hem) all over...
Edit: For some reason I missed the Penrose site at the link and skipped straight to the PDF short introduction. I am presenting somewhat redundant information above. Sorry!