Geometric Shapes With Embedded Magnets for Constructing Polyhedra (21mm)

Geometric shapes, around 20mm per side (actual edge size - 21.215mm) using 5mm magnetic balls. Make various polyhedron for education, or fidgeting.

2025-01-13 - Added Golden Ratio Rhombus model

WARNING: Magnets can be very dangerous, especially for small children. Swallowing even a small number of them can cause severe intestinal issues requiring surgery to fix! Do not allow anyone at risk of ingesting magnets to use them!!!  
https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Magnets 

No glue needed, as they are designed to be snapped together with the peg/hole arrangement.

You do need to purchase quite a few 5mm magnets depending on what you want to do with them. You need two per edge, so even basic models you would end up with 100+ magnets, and a full set would require 228 magnets.

A basic set would require:  
20 hexagons = 120 magnets  
12 pentagons = 60 magnets  
6 squares  = 24 magnets  
8 triangles = 24 magnets  
Total = 228 magnets

Since these are snap together parts, and need the magnets to rotate freely in their holes without falling out, they require a very well calibrated printer.

Print settings that I used reliably, with no post processing aside from inserting the magnets and snapping them together.
Prusa Mk4s  
Nextruder Nozzle .4 CHT  
0.15mm SPEED default settings (no supports, or brims)  
VoxelPLA+ (any color)  
Smooth PEI build plate

The triangles are quite stubby for this set, so they can't be used to make a tetrahedron, but they can be used to create a octahedron, icosidodecahedron, or similar, with enough of them printed.

They are designed such that the magnet does not protrude past the edge, so the parts click together solidly, and hold well.

The size was designed to work around the Speks brand magnetic “geode” fidget toys to expand the capability.  
https://www.getspeks.com/collections/shop-all-geode/products/geode-magnetic-fidget-set?variant=39969415725143

Be aware that the actual magnet balls on the Speks site are 2.5mm, not 5mm, so they are not a good source of magnets for this project. Most magnets on Amazon are also 2.5mm or 3mm, so it does take a bit of hunting around for the 5mm size magnets (the ones I purchased were from a 3rd party seller called Generic, and the balls actually measured 4.85-4.92mm, even though the product picture showed 5.00mm)