(Wall panel mosaic from 'The Fatal Quadrant' by Arthur J. Burks)

Now I understood — at least as far as the purpose went — the white squares that made the wall panel look like a checkerboard. Under each was a number. That number corresponded with one of the robots who marched this very minute along one of twenty-six compass bearings. into the deeper heart of Antarctica — and what his glaring eyes saw in the wastes. all of us there in the laboratory saw in the white square above that robot’s number. If, for instance, I wished to see what the eyes of Mr. Twenty were seeing at that identical moment, all I had to do was look at the white square on the wall panel above the figure twenty. It seemed almost as though I were walking in the place of Mr. Twenty...

Immediately I wondered if Sherman Geddes had thought to equip his robots with memory. I turned and asked him.

“Of course." he said. "Indelible records are made — within the brain of each robot — of everything he sees. When they come back we can further check our work by checking the brain of the robot whose photographic eyes saw those things. All we have to do is seat him and tell him to repeat his findings for us — and there it will be. on the square above his number!"