Expandable Bistable Spinner (Multi-Colour, No AMS Needed)

I designed this bistable spinner inspired by bistable auxetic structures. It expands and collapses with a crisp, clean snap, feels great in the hand, and makes an excellent fidget.

I enjoy multi-colour printing, but my AMS (Bambu’s multi-colour system) broke, so I designed it to be printed in two or more colours without AMS. To make the pattern appear as in the images, print different colours on different layers. In Bambu Studio with the Standard 0.2 mm profile, add manual pauses at 2.0 mm, 5.8 mm, and 7.6 mm, swapping filament each time. You will end up with four distinct colour layers that show the pattern well. If you have AMS, you do not need to pause; simply use the multicolour print profile.

This model prints without any support on Bambu P1S and X1C. I have not tested other printers yet, but if you need support, Tree supports should work and can be removed cleanly after printing.

There is also a small easter egg. The futuristic, geometric patterns are derived from bistable auxetic structures. A bistable mechanism has two stable positions and snaps cleanly between them, which is why the spinner locks open and closed with that satisfying click. The surface pattern is based on an auxetic cell—a structure with a negative Poisson’s ratio, meaning it expands outward in multiple directions when stretched rather than thinning like ordinary materials.

https://www.starryodyssey.com/design/expandable-bistable-spinner