The steel pot increases the adhesive force of the embedded disc magnet sixfold. The counter pole on the back is "redirected" to the front by the steel pot, so the circular contact surface of the steel pot is actually the magnetic counter pole to the disc magnet. This magnetic "short circuit", without air between the two poles, increases the adhesive force substantially.
This elevated adhesive force can only be reached through a direct contact with the counterpart. Even a small distance of a few millimetres will cause the magnetic attraction to cease.
The answer to why you can arrange pot magnets only side by side can be found under our FAQ
In 2011 the city of Zurich offered an interesting tour through the waste cogeneration plant "Hagenholz" in the trendy fifth district. To start off, the visitors met at a so-called "rendezvous cube".
Nine super-magnetic GTN-20 hold together a cube wall - flexible and sturdy.