Rare earth neodymium cube magnet is a very popular and versatile permanent magnet. Geometrically, they are cuboids with the same length, width and height, so you can't know the magnetic pole of a cube neodymium magnet without the help of other objects. To test the magnetic pole of a cube magnet, you can test the adhesion and repulsion of each cube side with a second same magnet. You can also use a magnetic pole detector or a magnetic pole probe to determine the magnetic pole.