I've worked through 5 versions of this. The final (fifth) version is wood stained and engraved with voronoi patterns on the sides.
Cut/Engraved with a Glowforge.
Parts:
plywood
https://smile.amazon.com/dp/B08NC1WRW7
magnets
https://smile.amazon.com/dp/B0936M3WPK
metal rods for hinge
https://smile.amazon.com/dp/B09W5Z5HDH
wood stain
https://smile.amazon.com/dp/B08CXHN791
anodized aluminum business cards
https://smile.amazon.com/dp/B01ISMGKQE
Voronoi pattern generator: