This is a fun little model that is super easy and quick to make! If you have a bunch of magnets laying around from various prints, this is a super fun way to put them to use!

I saw this idea on YouTube and decided to play around with a dozen variations of size until I finally came to this design for the optimal effect. I used two 20x3mm magnets in the center (although the actual size was 19.5x5.5mm) and twelve 6x2mm magnets around the outside. The polarity of the outside magnets repels, and the inside magnet attracts until they find an equilibrium that locks the other magnets in place without letting them touch. The magnets they are pulling/pushing on are two 8x2mm magnets.

I just printed this with PLA, but because of its small size and the strength of the magnets, I used 50% Cubic infill (you could probably get away with less, but the amount of time/material was negligible, so I just went high). I'll include the .3mf file in case you want to play around with different sizes. Since I have a 0.4mm nozzle, I left 0.8mm around the small magnet (between the edge and the small magnet as well as between the small magnet and the large magnet). I also made the holes 0.2mm larger than the diameter of the magnets, but depending on the tolerance of your printer, you may need to adjust that so the magnets have a snug fit (if they are too loose, they'll pop out and go all over the place).