Stackable Banana fridge magnets. Put a bunch aside when you don’t need them.

Single and multi-color printing models are included as STL and 3MF! They work with all current and usual multi color setups.

Instructions
Get 10 x 2 mm neodymium magnets, preferably in N45 or N52 strength. You will need two per banana. It might work with 10 x 1 or 10 x 3 mm magnets, too - but that is not tested.
Print as many bananas as you want. 18 of them form a full circle.
The little magnet cap is optional - It is 0.4 mm thick and will add to optics but reduce strength slightly. Decide if you want to print it or not and proceed accordingly.
Print the inserts. They have a small cut that serves as rotation help when aligned with the small cut inside of the bananas hollow part. There are two sizes provided. Depending on your magnet tolerance and cap choice, one of both will work fine. If you are not satisfied with the alignment, you can scale the insert slightly.
Glue the parts into the banana in this order: Magnet, Insert, Magnet, Cap (optional).
For each consecutive banana you need to make sure that the magnet alignment is correct. You can easily do this by assembling one top of your original banana. When inserting the bottom magnet, you can already feel if it is rotated correctly.
Enjoy!

Size of one banana: 73 x 45 x 18 mm