Configuring magnets in certain ways can enhance the magnetic properties of a magnetic assembly. The Halbach Array is one such configuration. First discovered by the late Klaus Halbach in the 1980's, the Halbach Array uses Rare Earth Magnets such as Neodymium to direct the magnetic field to one side of a particular array or arrangement.
Constructing a Halbach Array is very difficult as essentially you need to compress like poles together which effectively enhances the magnetic field also. Once the magnets are in the desired assembly the magnets can be held together with aluminium tape or a quick setting epoxy resin.