"The dates coincide with widespread disruptions on Qura-qua. Peoples vanishing from history, states collapsing, that sort of thing."

"That's right," said Richard, remembering the discontinuities. He lapsed into silence.

The somber gray cityscape moved beneath them. Ahead, Carson's navigation lights blinked red and white. Cheerful and brave against the eeriness. Hutch brought Carson up again on the display. "How long have you been out here, Frank?"

"Six years," he said. "Long time."

"I guess." His features betrayed no emotion. They were shadowed and highlighted by the illumination from his control panel. "Where's home?"

"Toronto. I was born in Edinburgh, but I don't remember any of it."

"Have you been back at all? For a vacation?" "No. I've been busy." Hutch knew that was unusual. Academy personnel were granted six weeks annual leave plus travel time. Carson was a workaholic.

Richard had been watching the patterns of blocks. "I wonder," he said, "why they're all cut to the same dimensions? Might they have had some sort of inflexible rock scoop? Only cuts one size? Then welds them together?"

Hutch put one of the blocks on the display.

"No," said Carson. "That's not it. The larger blocks aren't made of smaller pieces. They're just cut to be three, or eight, times as big. Whatever. Anyway, we're here. Look over to your left."

A tower rose from the general pattern of low-level obloids. But it was a tower with a difference: the thing was round. It was short, squat, about four stories high. It stood alone in a square.

Its roundness was remarkable. In that numbing display of parallel lines and right angles' and precise intersections, its simple circularity was a marvel, a masterpiece of invention.

They landed. Richard could barely contain himself during the cycling process, waiting for pressure to drop and hatches to open. Hutch, secure within her energy field, placed a restraining hand on his shoulder to remind him of the need for caution.

The tower was charred on the north side.

Carson opened his cargo door, and emerged with a small stepladder. Richard reassured his pilot, climbed out, and descended the handholds. A layer of dust covered the square.

At ground level, and out of the shuttle, Hutch felt the weight of the ages, empty streets and mock houses, mad geometry and ong shadows that had waited through the whole of human history.

Carson knew precisely what he was looking for. He walked to the tower, placed the ladder against it, adjusted it, tried it himself, and then stood aside and invited Richard to mount. "Careful," he said.

About five meters up, four lines of symbols protruded from 1 the marble. Richard climbed until he was at eye level with — diem, and used his lamp.

They possessed no resemblance to the exquisite symbols

Son lapetus. These were heavy, solid, blunt. Direct, rather than suggestive. Masculine. While he appraised them, Carson dropped a bombshell: "It's a Quraquat language."

Richard swayed on the ladder. "Say again? My understanding was that no one on Quraqua ever developed space travel."

"That's correct, Dr. Wald. We don't know much about these people, but we're sure they never had that kind of technology."

Hutch stood back to get a better look. "Maybe another kind of technology, then. Something we're not familiar with."

"Like what?"

"I don't know. If I could tell you, I'd be familiar with it."

"Well, it doesn't matter." Carson cut her off impatiently. "We know they had a horse-drawn civilization when people were speaking this language."

Richard was inspecting the symbols through a magnifier. "When would that have been?"

"Ninth millenium, B.C."

Same era. Hutch looked around at the blind oblongs and the long quiet streets. A chill worked its way up her spine.

"Would the speakers of this language," Richard asked, "be the same people who engraved the image of the Monument-Maker in the Temple?"

"Yes," said Carson. "The language is Casumel Linear C. It was spoken only over a range of about four hundred years."

Richard, still perched on the ladder, leaned back and peered up at the top of the tower. "Is this why Henry has pushed so hard at the Temple?"

Carson nodded. "Can you imagine what it will be like having an inscription from this place, and not be able to read it?" He shook his head in disgust. "The people who spoke the language inhabited the country around the Temple of the Winds. And they controlled the Temple itself at one point. We've been hoping to find a Rosetta stone. Or, failing that, to get enough samples of the writing to allow us to decipher it."

Hutch broke in. "I don't understand this at all. If the Quraquat never came here, how could they possibly have left a sample of their writing? Are you sure this is what you think it is?"

"No question," said Carson. "It's a perfect match."

"Then what are we saying—?"

"I would think," Richard said, "that the builders of this—

monstrosity—left a message for the inhabitants of Quraqua. To be read when they got here."

"About whatl" Hutch could scarcely contain her impatience.

"An invitation to join the galactic club," suggested Carson. "Or an explanation for Oz." Richard started down. "Who knows?"

Hutch looked at Carson. "Frank, how many of these ancient languages can we read?" "A few. Not many. Almost none, actually." "None." She tried to shake the fog from her brain. "What don't I understand? If we can't read any of these languages, what difference does it make whether we find a Rosetta stone? I mean, we're not going to be able to read the Rosetta, either. Right?"

"It won't matter. If we get the same text in three or more languages, we can decipher all the languages involved. Pro-vided we get a sample of reasonable size." Richard was back on the ground now. "If you've seen enough," Carson said, "there's something else you'll want to look at." "Okay."

"We need to go to the top of the tower." They walked back toward the shuttles. "We can use mine."

They climbed in. Carson left the hatch open. He adjusted his cap, and activated the magnets. The vehicle floated up the face of the tower.

"Is there," asked Richard, "another of these things on the other side of Oz?"

"Another round tower? Yes, there is."

"Another inscription?"

"No. Not another inscription."

"Interesting." Richard looked down. "Hey," he said, "the roof isn't level." He leaned out to get a better view. "It's the first slope of any kind we've seen here." "There's another," said Carson. "The other tower."

"Yes." They hovered just over the roof. "Frank." Richard Wald's silver eyebrows drew together. Is the location of the other tower a reverse image of this one?" "No." Richard looked delighted.

Hutch saw the point. "It breaks the pattern," she said. "A straight line drawn between the round towers does not pass through the central tower."

"A unique condition in Oz. Frank, does it happen anywhere else?"

"Nowhere that I know of."

"Good. Then we have only these towers to concentrate on." He swung around, trying to get his bearings. "The center of the city is where?"

Carson showed him.

"And the other tower?"

"Toward the north." He pointed. "Why?"

"Don't know yet. Frank, have you measured the angle of the roof?"

"No. I don't think anyone measured it. Why would we?"

"I don't really know. But look at it. The lowest part of it lies on the side closest to the center of the city. As you look out toward the wall, the slope rises."

"I don't follow."

"All guesswork so far. Is the same thing true of the other round tower?"

"I'm not sure I understand the question."

"You said the roof there is also angled. Is the roof on the other tower lowest where it's closest to the middle of Oz?"