Fire With Fire

steel. The stereobate-that’s the foundation-is actually risers of dressed stone, alternating with reinforced concrete. Probably the only reason the base held together all this time. The rebar was sunk a meter down, at even intervals all along the side.” He paused. “You know what it means, don’t you?”

Caine barely heard him, could not remember if he nodded or even waved farewell. He scrabbled up the berm and back toward the Marine lander. He was short of breath when he reached it, but not as a result of the exertion. Rather, he was overcome by a sudden, absolute, even desperate desire to begin his journey: to return home and discharge the burden of this final secret-the one which was the explanatory key to all the others…

Caine once again became aware of the faces ringing the round table. The looks were hard to read for a moment: fragments of many expressions were rippling up through the studied detachment of career diplomats and politicians. He saw shock, doubt, wonder, distrust, maybe even fear: too many threads, too tangled to separate.

They kept looking at him, as if they were waiting for more.

Nolan stood. “I think you see why we saved Mr. Riordan’s footnote for last. It is-singularly provocative. I’m sure there are questions: who’d like to start?”

Visser leaned forward. “You finished by saying that the presence of the rebar explains all the other secrets of what you found. What did you mean by that?”

Where to begin? “I’m going to jump ahead to the most important conclusion that can be deduced from it.” Caine took a deep breath. “Taken along with the local’s ability to point out the Sun as my place of origin, it means that we have been on Delta Pavonis before.”

There were sounds of restlessness among the delegates. “How long before?”

“I can’t be sure, but I’d say at least fifteen thousand years. Probably more like twenty thousand.”

The first moment of stunned silence spawned its opposite: Gaspard snorted the word “outrageous” through pinched nostrils; Medina laughed; Karagawa smiled; MacGregor raised his eyes toward the ceiling. But Sukhinin, Ching, and Hollingsworth only looked more thoughtful. Durniak’s eyes were wide as if she were already seeing how the logical dominoes inexorably fell toward this conclusion.

Nolan had his hand raised for order, but Caine was suddenly weary of having to rely on someone else’s authority: “Listen: do you want to hear why this conclusion is inevitable, or not?”

Sudden stillness. Nolan was hiding a pleased grin behind the hand upon which his jaw was resting.

Caine leaned forward. “First, the facts: the local’s indication of our star was absolutely unmistakable, once I realized what he was doing and what he was pointing at. And he did so repeatedly. Until I understood. I think it safe to say that there are no grounds for suspecting that I misinterpreted his gestures.”

“So once we’ve established that he does know where I came from, the question becomes: how could he know? There are two reasonable answers, excluding blind luck and divine inspiration. One: he learned this from us, directly or indirectly, since our arrival on Delta Pavonis in 2113-but neither his behavior nor our records show any possibility that this could have occurred. Two: that he and his people knew of us-and our star system of origin- before we arrived in 2113.”

Durniak was thoughtful. “Could they have visited us? Were they once a starfaring civilization?”

Caine nodded, impressed by the rapid flexibility of her mind. “That’s one possible mechanism to explain their prior knowledge of us. But the data argues against it.”

“Why?”

“Lack of gross physical evidence. Let’s use ourselves as an example. If Earth reverted to a primeval state, and never rose up from that again, later visitors would still be able to infer some of our contemporary technological capabilities from the alterations we made to the surface of our planet.”

“Such as?”

“Such as mountain passes and roadways that have been blasted out of solid granite, the plumb-straight line of canals, perfectly level roadbeds, old quarries, tunnels. The probability that the locals on Dee Pee Three could have reached Earth via supraluminal travel without having first gone through an industrial era is extremely unlikely. On the other hand, there is strong evidence that we were present on their planet. Long ago.”

Gaspard scoffed. Sukhinin-eyes narrowed, nodding-asked: “Such as?”

“Such as the main ruin.” Caine picked up his palmtop, switched it over to remote control mode, called up the first image on the room’s display screen: a view of the stairs leading up to the humble remains of the micro- Acropolis.

Gaspard sneered. “And how is it that their ruin proves our presence?”

“Because this is not their ruin; it’s ours.”

Chapter Twenty-Two

ODYSSEUS

Again, absolute silence. Then Ching leaned forward and spoke: “Please continue, Mr. Riordan.”

Caine wasn’t sure whether his claim, or Ching’s unprecedented decision to participate, made the greater impression on the rest of the delegates. “Thank you, Mr. Ching. Allow me to first suggest something that should be common sense: creatures tend to build what is comfortable and convenient to their own physiognomy. We place our windows at heights convenient to our heads and arms. We shape doorways so that they accommodate our dimensions as we walk.

“So, before we turn to the specifics of the two ruins on Dee Pee Three, let’s look at the creatures we think might have built them. Here is a rough anatomical study of the Pavonians.” Caine called up another image, superimposed on the mini-Acropolis: a “Da Vinci’s man” representation of Mr. Local. “In particular, I want to call your attention to the arrangement of the Pavonian legs and feet. They are, as you can see, splay-footed, and while usually plantigrade, they come up into a digitigrade stance when they run. Their foot also has a long, bifurcated back toe, evidently evolved both for stabilization and as a climbing aid, since they remain very arboreal. So the length of an adult Pavonian’s foot, from the tip of their front toes to the end of their rear one, is about forty-five centimeters, or roughly eighteen inches.

“However, at the main ruin, each riser of the stairs averages about thirty-six centimeters in width, or about fourteen inches. That’s much less than the length of a Pavonian’s foot. So if a Pavonian tried walking up these stairs using his leisurely plantigrade stance, three to four inches of the back of his foot would always be hanging over the edge of each riser, making this design not only stupid, but painful. Each step would be, in human terms, the equivalent of pounding one’s sole down on a narrow, hard transverse bar. The only way for Pavonians to avoid this discomfort would be to rise up on the ball of their foot, but without adopting the long, loping stride for which they employ that stance. In short, that would be like trying to tiptoe up a stone staircase in snow shoes.

“So, unless the locals are innately masochistic, the stairs on the main ruin were not made for the Pavonian foot. However, consider these stairs.” Caine summoned an image of the hidden amphitheatre.

“Here, each riser is fifty to fifty-one centimeters wide, but only ten centimeters high. With a width of fifty to fifty-one centimeters, these steps handily accommodate the length of the Pavonian foot. But why only ten centimeters high?”

He had meant it rhetorically, but Durniak, like an overeager student, supplied the answer: “Because they are reverse-kneed.”

“Exactly. Watch a dog going up stairs; the reversed-knee design of its leg is optimized for running and springing, but not for the close up-down movement of climbing stairs. The dog’s leg has to bend, pull back a bit, lift up, thrust forward, and then plant on the new surface. The more elevated the new surface is above the prior level, the more awkward this action becomes. It would be even worse for a biped with such legs, lacking the stabilizing contact of the two front limbs-but these problems are all eliminated by the stairs at the amphitheatre. They are, in fact, perfect for the Pavonians’ unusual leg and foot arrangement.”

The next image was of the alcoves and scalloped risers at the back of the arena. “Observe the tendency to