"A baroque device, extravagantly ornamented, but of obscure function, that was found on the desk of Captain Nemo. Closer investigation at the Acadamie Nationale has determined that contrary to our initial assumption, the underlying structure is not in fact a mobius loop. Mme Jaquinard has posited that the apparatus was constructed from a ladder roated through a circle of 720 degrees rather than the usual 360, with a most ingenious spacing of the internal structure overlaying an axial rotation of exacltly one half-turn, thus ensuring that it does not occupy its own space as it is rolled up. It is currently on loan to the British Museum."
This is a very popular model; it prints beautifully and is really affordable. I reccomend the stainless steel (which is actually a polished finish even though that's not in the description) and the polished bronze steel. Do have a look using the roateable model, the stationary pictures hide the inner faces, and there's a lot of pleasing detail hidden within. As well as a pocket sculpture* this makes a great pendant with a steampunk feel, just add some 2mm leather cord to hang it from.
*Pocket Sculptures: Art to carry around with you! I think it's wrong to view art as something you just put on a shelf and admire. We all love to have in our pockets nice beautiful objects we've found - pebbles, driftwood, pretty stones and so on - and to show them to our friends. I design affordable and beautiful artworks that you can keep with you in your pocket, with satisfying shapes and textures that make you smile.