Sphericons

Chris K. Palmer modeled these novel Sphericons based on a mathematical discussion by Colin J. Roberts and Paul J. Roberts. His models included 4mm holes to accommodate widely-available 3.2mm magnets (like these) plus glue to cement them into place.

I scaled to model to 75% so the holes would be 3mm, slightly smaller than MagCraft N5NO566 disc magnets (3.2mm x 1.6mm). The resilient PVC material had sufficient 'flex' to permit the magnets to be forced into them.


Once the magnets were installed, I briefly soaked the parts in PVC welding solvent.


The solvent caused the PVC material to return to its square-ish shape around the magnets, securing them neatly in the holes.


The magnets allow the pieces to be paired to form round, solid objects. The pairing on the left can roll in a straight line, whereas the pair on the right can roll in a circular path.


But the same pieces can be paired so the curves look quite different. These pieces can be rolled along irregular paths.


Here's how the sphericon at left would roll. It follows a straight path with an occasional backstep.


And here's it's counterpart, at right in the previous picture. Its path is a bit more crooked.