A ridiculously detailed 4th order Hilbert curve* in 3D. Two corners are rotated so that the curve forms a loop.Thickness and gaps 1.5 mm.
See http://www.shapeways.com/model/109525/small_hilbert_cube_variation.html for a 1 mm version and http://www.shapeways.com/model/111039/tiny_hilbert_cube_variation__1_5mm.html for a 3th order 1.5 mm version.
* Actually Hilbert cube seems to have a different meaning.
4.652 w x
4.652 d x
1.831 w x
1.831 d x