I had read in the story-cube that the speed of light was a universal limit; that in a thousand years of experimentation-despite any number of false dawns-no one had ever managed to circumvent it. This had made me feel hemmed in and claustrophobic-it was like being told I must never run or skip down the long, dreary corridors of the house, but must walk instead, with my neck straight and my hands held behind my back. I felt affronted, as if the speed of light was a personal assault on my liberty. Why should I not go as fast as I pleased? Why should I not skip and run? But I could no more explain why the speed limit existed than I could explain why two and two did not make five. It was simply the way things were, one of those rules-like the edict not to visit certain parts of the house-that were not to be questioned.