"Lethe. I can't believe they fell so far. They've become utterly dependent on that artificial biosphere. They're reduced to technologies of stone and wood--"

"But they survived," Eve said. "Humans survived, even beyond the evacuation of the Xeelee. In a world that cared for them. You could argue this is a Utopian vision..."

"This world of theirs, with the Shell, is a four-dimensional sphere. No wonder they couldn't figure it out."

I thought of three-dimensional analogies. Allel's people were like two-dimensional creatures, constrained to crawl over the surface of a three-dimensional globe. Home and Shell, the twin worlds, were like lines of latitude, above and below -- each unbroken, each apparently cupping the other. Just as the diagrams in the "City" had tried to show them.

"But they were capable of understanding," Eve said. "After a million years, humans had adapted in subtle ways. Allel had the capacity to visualize, to think in higher dimensions. She could have understood, if someone had explained it to her. As those diagrams in the place she called the City were meant to. And in time, she would figure out some of it..."

"They were trapped," I said. "In a prison of folded space-time."

"Perhaps," said Eve. "Perhaps. But they didn't give up..."

The Eighth Room

The Eighth Room

A.D. 4,101,266

Teal slept through dawn.

He woke with a jolt. There was the faintest crack of red around the teepee's leather flap.

After all his planning... it would be broad daylight by the time he reached the bridge anchor.

But, he reflected ruefully, there was a certain irony. The dawn had been too feeble to wake him -- and that was the heart of the problem.

The Sun was going out. And today Teal was going to try to fix it.

With a fluid movement he slid off the pallet and stood in the darkness.

Erwal's breathing was even and undisturbed. Teal hesitated; then he bent and touched his wife's belly, his fingertips exploring the mummy-cow skin blanket to find the second heartbeat beneath.

Then he pulled on his clothes and slipped out of the teepee.

His breath steamed. Dawn was an icy glow; a roof of snow-laden cloud hid all sight of Home, the world in the sky.

He walked softly through the heart of the little village. The ground was corrugated by mummy-cow hooves. He stepped around piles of bone needles and broken stone tools, past heaps of lichen and moss gathered to feed the cows.

Frost crackled.

He glanced about uneasily. Nobody knew what he was planning today, and he didn't want to be spotted by any early risers...

But all the dozen teepees were silent. Even the one belonging to Damen, Teal's elder brother. If Damen knew what he was up to, he'd knock Teal senseless.

He found himself tip-toeing away like a naughty child.