Due to a lack of round magnets, I decided to make an alternative model using three cubic magnets (5 x 5 x 5 mm). Please note the polarity when mounting the magnets. It is best to mark one pole of the magnets with a colour to indicate the polarity. In certain configurations the magnets can push each other out of position. (This is not fun if the glue is not cured.)
The author remixed this model.
Three cubic magnets (5 x 5 x 5 mm) instead of two round ones.