Flat square tabs or sheets of plastic, different sizes and colors, baffled her, but then she got it: these were data disks, old magnetic media. And those big, round, flat black plastic things were analogue audio media, a mechanical system. You stuck a needle in a spiral scratch and spun the thing. Biting off more sandwich, she stepped past Tessa for a better look. There were reels of fine steel wire, ragged pink cylinders of wax with faded paper labels, yellowing transparent plastic reels of quarter-inch brown tape...