A play and instruction means on the basis of spherical elements, each element being an assembly of a hollow, spherical envelope made of a non-magnetizable material, in particular a synthetic plastics material, and a permanent bar-like magnet positioned within the envelope, said magnet having head faces curved analogously to the spherical envelope. The weight of the non-magnetic material processed in the spherical element is minimized relatively to the magnetic strength of the bar-like magnet.
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