It spread out around me, racing away from my viewpoint in all directions like nothing so much as a huge magnification of one of the spiral steps we had used to get down from the gantry. Steel grey, stippled every few metres with a nipple-like swelling, receding to infinity. The sky above was a paler shade of the same grey with shiftings that seemed vaguely to suggest bars and antique locks. Nice psychology, assuming any of the felons interrogated had anything but race memory of what an actual lock looked like.