Magnetic Disks Instead of Microchips
On a table lies a handful of round magnets. As long as no one touches them, they lie in disarray. But send a short current pulse through them, and each disk flips: the north pole swaps with the south. Neighboring disks push each other with their fields, like people in a crowded queue, and the whole handful arranges into a pattern that depends on which way the magnetic wind blew and how warm it is around.