Slightly off-topic, but if you're interested in SFC's in general (in any number of dimensions) then Herman Haverkort's work should definitely be of interest, in

Slightly off-topic, but if you're interested in SFC's in general (in any number of dimensions) then Herman Haverkort's work should definitely be of interest, includes a new scheme for curve classification. Sixteen space-filling curves and traversals for d-dimensional cubes and simplices (2018) https://arxiv.org/abs/1711.04473 https://arxiv.org/abs/1711.04473 BTW, Haverkort has fascinating application: he uses SFC traversals to generate music. To my ear, they sound surprisingly good. http://herman.haverkort.net/doku.php?id=sound_of_space-filling_curves http://herman.haverkort.net/doku.php?id=sound_of_space-filli...