mosaic of colored tiles, so fantastically involved that Alvin did not even attempt to unravel it.
"Look at this mosaic, Alvin," said the Jester. "Do you notice anything strange about it?"
"No," confessed Alvin after a brief examination. "I don't care for it-but there's nothing strange about that."
Khedron ran his fingers over the colored tiles. "You are not very observant," he said. "Look at these edges here-see how they become rounded and softened. This is something that one very seldom sees in Diaspar, Alvin. It is wear-the crumbling away of matter under the assault of time. I can remember when this pattern was new, only eighty thousand years ago, in my last lifetime. If I come back to this spot a dozen lives from now, these tiles will have been worn completely away."
"I don't see anything very surprising about that," answered Alvin. "There are other works of art in the city not good enough to be preserved in the memory circuits, but not bad enough to be destroyed outright. One day, I suppose, some other artist will come along and do a better job. And his work won't be allowed to wear out."
"I knew the man who designed this wall," said Khedron, his fingers still exploring the cracks in the mosaic. "Strange that I can remember that fact, when I don't recall the man himself. I could not have liked him, so I must have erased him from my mind." He gave a short laugh. "Perhaps I designed it myself, during one of my artistic phases, and was so annoyed when the city refused to make it eternal that I decided to forget the whole affair. There I knew that piece was coming loosel"
He had managed to pull out a single flake of golden tile, and looked very pleased at this minor sabotage. He threw the fragment on the ground, adding, "Now the maintenance robots will have to do something about it!"
There was a lesson for him here, Alvin knew. That strange instinct known as intuition, which seemed to follow short cuts not accessible to mere logic, told him that. He looked at the golden shard lying at his feet, trying to link it somehow to the problem that now dominated his mind.
It was not hard to find the answer, once he realized that it existed. Khedron "I see what you are trying to tell me," he said to Khedron. "There are objects in Diaspar that aren't preserved in the memory circuits, so I could never find them through the monitors at Council Hall. If I was to go there and focus on this court, there would be no sign of the wall we're sitting on."
"I think you might find the wall. But there would be no mosaic on it."
"Yes, I can see that," said Arvin, too impatient now to bother about such hairsplitting. "And in the same way, parts of the city might exist that had never been preserved in the eternity circuits, but which hadn't yet worn away. Still, I don't really see how that helps me. I know that the outer wall exists-and that it has no openings in it."
"Perhaps there is no way out, answered Khedron. "I can promise you nothing. But I think there is still a great deal that the monitors can teach us-if the Central Computer will let them. And it seems to have taken rather a liking to you.
Arvin pondered over this remark on their way to Council Hall. Until now, he had assumed that it was entirely through Khedron's influence that he had been able to gain access to the monitors. It had not occurred to him that it might be through some intrinsic quality of his own. Being a Unique had many disadvantages; it was only right that it should have some compensations.
The unchanging image of the city still dominated the chamber in which Arvin had spent so many hours. He looked at it now with a new understanding; all that he saw here existed-but all of Diaspar might not be mirrored. Yet, surely, any discordancies must be trivial, and, as far as he could see, undetectable.
I attempted to do this many years ago," said Khedron, as he sat down at the monitor desk, but the controls were locked against me. Perhaps they will obey me now."
Slowly, and then with mounting confidence as he regained of the wall we're sitting access to long-forgotten skills, Khedron's fingertips moved over the control desk, resting for a moment at the nodal points in the sensitive