A 3-dimensional version of the Hilbert space filling curve.
As shown in the photos, if printed in one of the "Strong & Flexible" plastics, it can be used as a bracelet or hair accessory. It takes a little time to reform back as a cube after being stretched, but it seems that leaving it overnight does the job.
4.44 w x
4.44 d x
1.748 w x
1.748 d x