"But what really happens is that the antineutron is created at that final impact and moves back through time to initiate the creation of the other particles! Bizarre enough for you? And so this particular Feynman picture is a closed loop. A vacuum diagram. The particles come from nothing and return to nothing." He grinned. "We're here because we're here because--"

Green raised one massive uniformed arm, pushed Taft away easily, muttered something Paul couldn't hear.

Paul closed his eyes, hoping to make the incomprehensible Universe disappear into the vacuum from which it had sprung.

The approaching Edge was a knife-blade across the stars. The car climbed the one-in-one slope ever more slowly, finally stopping a hundred yards from the rim. "Come on, Paul," Green said. "We walk from here." Briskly he helped Paul seal himself into a light, one-piece pressure suit. "And go easy. Remember we're that much further from the Lump's center of mass; gravity is only about half what it is in the City."

Paul climbed through the car's membranelike airlock. A handrail had been bonded to the surface a few yards from the car. Paul stumbled towards it. The apparent forty-five-degree slope was without purchase, and his motions felt slow and dreamlike, as if he were underwater.

Clinging closely to the rail he turned and surveyed the Sugar Lump.

Beneath his feet was a hillside of glowing glass. Shadows bigger than cities moved through it. Paul knew the Face was a square six thousand miles to a side, and he had half-expected to see details of far Edges and Corners from this vantage point; but beyond a few hundred miles the surface collapsed in his vision into a single, shining line of light. Sugar Lump City was a low dome of blue, improbably clinging to the center of the line.

"Paul," Green said softly. "Look up."

Paul craned his neck. A Spline warship swooped overhead, no more than ten miles from the Edge. Paul could make out valley-sized wrinkles in the fleshy sphere, weapon emplacements twinkling in deep pocks. Finally the warship sailed over the Edge of the world, rolling grandly.

"They know we're here," Green said. "That was a salute roll."

His voice seemed to come to Paul from far away. A sense of distance swept over him; it was as if he were shrinking, or as if the Universe were receding in all directions.

"Paul?... Are you okay?"

"What's wrong with him? Damn it, the kid's a liability."

"Take it easy, Taft. Sometimes this state of semifaint is a prelude to his heightened awareness phases. Come on, help me get him to the Edge."

The words swam by like fish. Green and Taft stood to either side of him, grasping his arms. They were figures of wood and paper, moving with dry rustles. The light of the Lump burned through them.