The second tab: 'Where digital meets Nature' has a brief summary of how it works. Sounds like a grid of magnets:

"In the front, the display has a basin comparable to an acquarium in which Ferro Fluid can move freely. Behind the scenes powerful electromagnets enable Ferollic to influence the fluid’s shape, to pick it up and move it around. Both modules, the basin and the electronics, sit secure in an aluminium frame."