Thanks for sharing this article. I actually have a few puzzles that
more or less follow these principles. Perhaps the best example is
"Triple Cross", which you can see a picture of here:
You can also make the regular 3D Rubik's cube a little more like these
by restricting yourself to only twisting certain faces. For example,
scrambling and then solving regular Rubik's cube by only twisting two
adjacent faces is much harder then solving it normally.
It might be interesting to play with the 4D version of the puzzle in
that way, something that had never occurred to me. I bet randomizing
and solving the 4D puzzle by twisting only two or three adjacent
"faces" would be harder than or at least very different from solving
the puzzle in the normal way.