Dura flexed her legs; the Waving carried her easily through the Air. She moved away from the hulk of the "Pig" and toward the walls of the chamber. Tentatively she reached out a hand, placed it cautiously on the gray wall material. Beneath her fingers and palm its smooth perfection was unbroken. It was cool to the touch — not uncomfortably so, but a little cooler than her body.

"Dura." Hork sounded excited; he was inspecting the wall display Dura had seen from within the "Pig." "Come and look at this."

Dura Waved briskly to Hork; side by side they stared at the display.

Two circles, differing in size, had been painted on the wall. The larger was colored yellow and was perhaps a micron wide. The color was deepest at the heart of the circle and lightened, becoming almost washed out, as the eye followed the color out to the edge of the circle. The disc was marred by a series of blue threads which swept through its interior — a little like vortex lines, Dura thought, except that these lines did not all run in parallel, and in places even crossed each other.

Each blue line was terminated by a pair of tiny pink tetrahedra, one at each end. Most of the tetrahedra had been gathered into the center of the disc, so that the lines looped around the heavy amber heart of the disc. But five or six of the lines broke free of the knot at the center. One of them terminated at a pole of the disc, just inside its surface. The rest of the lines led, in wavering spirals, out of the disc itself, and crossed the empty space of the intervening wall to the second, smaller circle; a half-dozen tetrahedra jostled within the small circle like insects.

Dura frowned, baffled. "I don't understand. Perhaps these little tetrahedra have something to do with the wormholes..."

"Of course they do!" Hork's voice was brisk and confident. "Can't you see it? It's a map — a map of the entire Star." He traced features of the diagram with his fingertip. "Here's the Crust; and within it — this outermost, lighter band — is the Mantle, which contains the Air we breathe. All the world we know." His fingertip gouged a path into the heart of the Star image. "These darker sections are the underMantle and the Quantum Sea — and here's the Core."

"And the tetrahedra, the threads connecting them..."

"...are maps of the wormholes!" His eyecups were wide and filled with the gray light of the chamber. "Isn't it obvious, Dura? Look." He jabbed at the "Core." "And here are the wormhole Interfaces, brought into the Core by the Colonists after the Core Wars. Most of the Interfaces, anyway. And so the wormhole corridors — marked by these threads — lead nowhere but back to the Core."

The implications of his words slowly sank into her. "So there are many wormholes — dozens, hundreds — not just the one we traveled in?"