I made this fast printed and very useful paper clip magnet cube, just print the bottom and then choose out of four tops which are 30x50mm or 50x50 mm, with or without tough.

After printing just stick up to 9 magnets (10mm x 3mm or 8mm x 3mm) into the holes at the back of the top and then glue the bottom part at place.

For a little more weight, you can add sand or something else and only then close the cube. This makes it look even more high-quality and stands more firmly on your desk.