The best triply periodic minimal surface ever!

I put a bigger one here.

Ball trapped in a spiral cage

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.