This page contains renderings of the third-order approximating curves of several different three-dimensional Hilbert curves. The names of the curves are explained in:
The figures below are produced with the software that comes with the article, plus a POV-ray include file (currently not included in the package) tailored to certain classes of curves. The curves shown below are not a representative selection of three-dimensional Hilbert curves: they were chosen to look good with the styles of rendering used here.