These auxetic structures swivel and expand in surprising ways! This is a 3x3 variation has stacked hinges to add strength and rigidity along the Z plane... a.k.a. more smooth & satisfying fidgeting!
Printing Guidelines
Fairly loose requirements, just make sure your printer isn't overextruding and has decent cooling so none of the parts fuse. I used 0.16mm layer height, 3 shells. No supports!