First of all - it can be solved !!! If you have solved - please do not spoiler
You will need 6 magnets 4mm x 1mm. Use glue for mounting. Start from one side - place all magnets in one polarity
Then on this side place a free magnet. It will fit in the same polarity. Then just press the other side (with a little glue inside the holes) and you are done.
I add a text modifier to personalize it - now you can easy change.
Each part is named in the design - just change the side_text property, as on screenshots.
For closing the puzzels, the best option is to put two parts on each side and close them at the same time - you will get nice boxes.