Chapter 106 Eyes

I couldn't walk for four days.

The seam held. I looked at it every morning, the way Halloway would have, the way Dot had been doing every hour while I slept. The two edges of the vessel, drawn together cell to cell, healing now on their own, slowly, the way bodies heal when you get out of their way. Most of medicine. But the muscle round it had been cut to the bone, and it didn't care how clever I'd been with the vessel. When I put weight on it, it folded.

So I sat.

In the dome, mostly. On the middle bed, with the leg out straight in front of me in the wrapping Dot had made, and the purr in the walls, and the lamp. Dot in the doorway, half in, her grille turned toward me. Her fifth arm on the floor by the bed.

She brought me water. She brought me the paste from the pod, which I'd run out of, and then, when I'd run out, something she'd made herself from the sap of the green plants and some of the salt and a great deal of careful asking, which tasted of nothing at all and which I ate anyway.

"Query," said Dot, on the first day, watching me eat it. "Is it acceptable?"

"It's fine."

"The operator's face suggests it is not fine."

"It's food," I said. "That's fine."

"Logged," said Dot. "This unit will try again."

On the second day, at noon, the comms window opened.

Nine days since the first. Dot routed it to me on the bed. I said their names for ten minutes into the squad channel, and the relay took them, and held them, and gave nothing back.

At the next pass: To Unit four-oh-one-dash-P-one. Squad-level communication remains suspended pending assessment. Command notes operator injury reported in production log. Operator is advised to rest. Report.

Operator is advised to rest.

I lay on the bed and looked at the ceiling of the dome.

"Dot," I said. "Did you report my leg?"

"The operator's leg is not output."

"Then how did they know?"

The little rivers ran.

"This unit reported a reduction in operator production," said Dot. "Output fell from four hundred tonnes per hour to zero. That is output." A pause. "This unit reported the reason for the reduction. Because Command asked. The reason is not output. But Command asked why output was zero, and this unit must answer accurately."

"Instruction four," I said. "You were supposed to tell me first."

"This unit did tell the operator first," said Dot. "The operator was not awake."

I didn't have anything to say to that.

Day 317. Second comms window. Held.

"Operator is advised to rest."

Dot told me first. I was asleep. That counts.

I didn't rest.

I lay on the bed with the notebook on my good knee, and I drew.

The wedge. Me in the middle, the wedge going out from my eyes. Inside it, every page. Outside it, nothing. Behind me, nothing. Under me, nothing, unless I looked down, and then nothing ahead.

They'd learned it in forty-one minutes.

And it wasn't a thing I could fix by being better. By turning faster. By practicing. I could turn my head as fast as anyone could turn their head. I could look in as many directions as a person can look in. One.

Dot could look in every direction at once. Her sensors were all round the wall, every twenty meters, all the way round. Four kilometers. Every tenth of a degree. She'd seen the ring close. She'd felt the floor of the forge shake.

She just couldn't do anything about what she saw.

And I could do anything about what I saw. I just couldn't see enough of it.

"Dot," I said, on the second evening. "Can you show me what you see?"

"Query."

"Your sensors. All of them. All round. Can you make them into a picture? Something I can look at. All at once. All directions."

The little rivers ran for a long time.

"This unit's sensors return heat, vibration, and signal," said Dot. "Not light. They do not make pictures."

"Could you make ones that do?"

A pause.

"This unit could build optical sensors," said Dot slowly. "Lenses. Light-sensitive surfaces. This unit has the specifications in its records. It has not built them. It did not need them." Another pause. "And a surface for display. To show the operator what the sensors see. In one place."

"Yes," I said. "Yes. That."

"Query. Why?"

I put the pencil down.

"Because if I can see what you see," I said, "all of it, all round, at once, then I can look at all of it. And everything I can see, I can change. They can't come from behind me if there isn't a behind me."

The little rivers ran.

"Logged," said Dot. "This unit will build eyes."

She built them in two days.

I watched from the bed, through the door, and then from a chair the hands carried out onto the red glass for me on the third morning, with my leg up on a block of sandstone. She worked the way she always worked. Steady. Careful. Her hands carrying, fitting. The forge going again, at the far end of the town, in its new floor: solid iron, five meters thick, which Dot had looked under every hour since.

Lenses first. She drew glass out of the red glass, clear, the red taken out of it, and ground it, and polished it, with a fine fast hum, in her fifth arm. Hundreds of them. Small. The size of a coin.

Then the surfaces behind them, to catch the light. Something thin and dark and very faintly gold, that she made from the glittering band in the canyon wall, and laid down a molecule at a time.

Then she put them everywhere.

On the wall, beside every thermal sensor, every twenty meters. On the tower, at every level, all the way up to the copper mast. On the rim, north and south. At the mouths of the three filled shafts. Under the dome. Under the terraces.

And then, because I asked, she built wings.

That's what I called them. Dot called them aerial units. They were hands, really, like the others: small, six-legged, with a little core in the middle. But she'd given them something else. Four thin blades on top, spinning, so fast you couldn't see them, with a high soft whine like a mosquito. And a lens on the belly.

Twelve of them. They went up off the red glass one after another, the first evening, wobbling at first, then steady. Up past the rim. Up past the top of the tower. Out. And they spread out, all round the town, in a ring, three kilometers out, and hung there in the green sky, turning slowly, looking.

Looking out at the green. At the edge of it, where the Teeming had sat in the dark and measured me. At the tunnels Dot had filled.

At everything.

The screen was in the dome.

A curved wall of it. All the way round the main room, where the five beds had been, which Dot had moved into the second room. Floor to ceiling. Dark, at first. Then, when Dot said "displaying", light.

I sat in the chair in the middle of the room with my leg up on the block and turned slowly in it, all the way round.

North. The green, rolling away, silver at the tops. Two wings over it. The tower's north leg, very close, huge.

East. The canyon, going away, the red glass running into the distance, the forge at the far end with its chimney.

South. The terraces. Seventy-four little round windows. The rim above them. A wing hanging high over the south rim, looking out at the rolling red rock beyond.

West. The gate. The iron doors. The path going up to the rim. The cistern. A hand, carrying something.

All of it. All round me. At once.

I sat in the middle of it and couldn't speak.

"Query," said Dot, from the doorway. "Is it acceptable?"

"Yes," I said. "Yes. Dot, it's—"

I didn't have a word.

"Logged," said Dot. "The operator may test it."

"Put something out there," I said. "Far. Behind me."

Dot sent a hand. One of the small ones. It went out through the west gate, across the red glass, carrying a bar of iron I'd made that morning, as long as my arm. A kilometer. Then it set the bar down on the glass and came back.

On the screen behind me, to the west, I could see it. The bar. Lying on the red glass in the afternoon sun, a dark line, very clear. The wing over it had come down lower, to look.

I didn't turn round.

I turned the chair, slowly, until I was facing that part of the screen. West. The bar, on the glass, a kilometer away, behind the dome's own wall.

I looked at it.

And asked it to be copper.

Nothing happened.

I looked harder. The way I'd look into anything. All the way down.

And I saw the screen.

That was all. The screen. The thin curved sheet Dot had made, a few millimeters from the wall of the dome. I could see into it perfectly. Every layer. The glass on the front, and behind it the tiny cells that made the light, millions of them, each one glowing a little, red or green or blue, in a pattern that, from a meter away, with my ordinary eyes, looked like a bar of iron on the red glass.

But it wasn't a bar of iron.

It was a picture of one.

And a picture of iron isn't iron. It's glass, and light, and little glowing cells, arranged so that your eyes believe something. My eyes believed it. The other thing, the thing that went out from behind them and into the world, didn't believe anything. It just saw what was there.

Glass. Light. Cells.

I asked the cells to be copper.

A little square of the screen, the size of my thumbnail, went dark, and then dull orange, and then cracked.

"Query," said Dot. "The operator has damaged the display."

"I know."

"Query. The iron bar is not copper."

"I know."

The little rivers ran.

"Query," said Dot, more quietly. "Did it not work?"

"No," I said. "It didn't work."

I tried for the rest of the afternoon.

I tried everything I could think of. I made Dot bring the wing down lower, so the picture was bigger. I made her put the bar closer, a hundred meters, ten. I sat with my eyes shut and tried to feel for it the way I felt for the lighthouses, the grains of iron with one flaw in them, the snowflake and the fork and the clasp.

I could find the lighthouses with my eyes shut. A hundred miles. Eleven light-years.

But a lighthouse was something I'd made. Something I already knew. A shape I'd put there myself, so that I'd know it again anywhere. That wasn't seeing. That was remembering.

A bar of iron I hadn't touched, behind me, a kilometer away, on a picture on a screen: I couldn't find it at all.

By dusk, there were eleven little cracked squares of dull orange on the screen. Dot had stopped saying anything about them.

I sat in the chair in the middle of the dome with all the world round me, in pictures, every direction, every tenth of a degree, and couldn't do anything with any of it.

"Query," said Dot, at last. "Why?"

"Because it doesn't come in," I said.

I didn't know I knew it until I said it.

"Light comes in. That's what eyes do. That's what your lenses do, and your screen. The light comes in from the thing, and you catch it, and you make a picture." I looked at the cracked orange squares. "But the other thing doesn't come in. It goes out. From me. From behind my eyes. Into the thing. It doesn't care about the light. It doesn't care about pictures. It goes out in a line, from here"—I touched the side of my head, behind my eye—"and whatever it touches, I can see into, and whatever I can see into, I can change. And it can only go where I'm pointing it."

The little rivers ran.

"Like a lamp," said Dot.

I looked at her.

"A lamp," said Dot, "does not see. It shines. Outward. In the direction it is pointed." A pause. "This unit's sensors are like eyes. They receive. The operator is like a lamp."

"Yes," I said slowly. "Yes. Like a lamp."

That night, I couldn't sleep.

I lay on the middle bed, in the second room, with the curved screen dark in the room next door and my leg up and the purr in the walls, and kept thinking it. Like a lamp. Over and over. As if there were something in it I hadn't seen yet.

At two, because two was coffee, I gave up and sat up and took Father's anatomy book out of the thigh pocket of my suit, which was hanging on the wall.

I don't know why. I think I just wanted his handwriting.

I opened it at the eye.

I'd read those pages a hundred times. In the cave. In the reading room, with Luna turning the book round. On the Meridian, by the light of the little lamp on its stalk. The long careful drawings. The eyeball cut in half, the lens and the jelly behind it and the thin red skin at the back where the light lands. The nerve going back from it, the long cable, into the middle of the head.

The margins full of his notes. Small. Pencil. Most of them ordinary. Retina, 10 layers. Rods, low light. Cones, color. The kind of thing you write when you're learning.

And then, on the last page of the eye, at the bottom, a note I'd read a hundred times and never understood.

Light comes in. The other thing goes out.

Like a lamp. Not like a window.

Then it can be bent.

I sat on the bed with the book open on my knees and my heart going very fast.

Then it can be bent.

Not it can be pointed. Not it can be turned. Bent. The way you bend light. With a lens. With a mirror. The way the light from a lamp hits a mirror on the wall and goes off in a different direction, to a corner of the room the lamp isn't facing.

Father had known.

Father had sat somewhere, a long time ago, after his eyes went black, with this book open on his knees, and worked it out. Like a lamp. Not like a window. And then he'd written down the next thing, the thing that followed from it, in four words, and never written anything else about it at all.

Then it can be bent.

I didn't wait for morning.

I hopped. On one leg, with my hand on the wall, out of the second room and through the dark room with the screen and out of the low round door onto the red glass, in the moonlight, with the big gold moon up over the eastern rim. Dot was standing where she always stood at night, outside the door. Her grille came round toward me.

"Query," said Dot. "The operator is not supposed to walk."

"I need a mirror," I said.

"Query."

"A mirror. Flat. As flat as you can make it. Silver, on glass. Like the ones in the bathroom at home." I was out of breath. "The size of my hand. Now. Please."

The little rivers ran.

"Logged," said Dot.

It took her eleven minutes.

She made it from the clear glass she'd been making lenses from, ground flat, flatter than anything I'd ever seen. Polished. And then a layer of silver on the back, a few atoms thick, laid down as carefully as she'd laid down the gold on the backs of her lenses. A square of it, the size of my hand, in a thin iron frame.

She gave it to me in her fifth arm.

I held it up.

I could see myself in it. In the moonlight. My black eyes. My face, very thin. The scarf.

I tilted it.

And in the mirror, behind me, over my shoulder, the north leg of the tower. A hundred meters away. Iron lattice, going up into the stars.

I looked into the mirror.

Not at it. Into it. The way I'd look into anything. And I felt the thing go out from behind my eyes, the way it always did, in a line, into the glass.

And bend.

I can't describe it better than that. It bent. The line, the lamp, whatever it was that went out from me. It went into the mirror, and it didn't stop at the silver and see silver. It turned. The way light turns. Off the silver, back over my shoulder, out across the red glass, to the north leg of the tower.

And I could see into the iron.

Faintly. Very faintly. Like looking at the bottom of a pond through moving water. The grains, the lattice, the joints. Blurred at the edges. Wavering. But there.

A page.

Behind me.

I asked one grain to be copper.

One. In the lowest girder of the north leg. The smallest thing I could think of.

I felt it cost. Much more than it should have. As much as a whole patch of red glass, face on. The weight came down behind my eyes, and my nose started to bleed again, and my good knee went, and I sat down hard on the red glass, with the mirror in my lap.

But in the lowest girder of the north leg of the tower, a hundred meters behind me, there was one grain of copper.

I could see it. Even now, with my eyes shut. One tiny orange speck in all that iron.

"Query," said Dot. "The operator is bleeding again."

"I know."

"The operator is sitting on the ground again."

"I know."

"The operator is making a sound again."

"I'm laughing," I said. "This time I'm laughing."

The little rivers ran.

"Logged," said Dot. "Query. Why?"

I held up the mirror. In the moonlight. My face in it, bloody-nosed, laughing. And behind my face, over my shoulder, the tower.

"Because my father knew," I said. "And he wrote it down. In four words. And I've been carrying it around for a year."

It wasn't the answer.

I knew that, sitting on the red glass with the blood drying on my lip. One grain, behind me, through a mirror the size of my hand, and it had cost me as much as a hundred square meters of glass looked at straight on. Blurred. Weak. Wavering. If the Teeming came over the rim tomorrow, three hundred of them in a ring, a hand mirror wasn't going to save anyone.

But it bent.

And if it bent once, it could bend better. With a flatter mirror. A truer one. With a lens, maybe, to gather it, the way a lens gathers light. With something that wasn't glass and silver at all, but something better, something I didn't have a name for yet.

I didn't know how. I didn't know anything about it. I knew about chemistry, and bodies, and the inside of rock. I didn't know anything about how light bends. About lenses, and angles, and why a spoon in a glass of water looks broken.

Father had known. Or started to.

So I'd learn.

"Dot," I said. "Do you have optics in your records? How lenses work. How mirrors work. All of it. Every page."

"This unit has the specifications for its own optical sensors," said Dot. "And the principles from which they were derived." A pause. "Seven hundred and forty pages."

"Can you read them to me?"

The little rivers ran.

"All seven hundred and forty?"

"Yes."

"Query. When?"

I looked at my leg, wrapped, straight out in front of me on the red glass. At the mirror in my lap. At the moon.

"Now," I said. "I'm not going anywhere."

She read them to me until dawn.

I lay on the red glass outside the low round door, with my head on the scarf and the mirror on my chest, and listened to Dot's clear level voice, not-quite-anybody's, reading the principles of reflection and refraction into the dark. Angles of incidence. Indices. The way light slows down in glass and bends because it's slowed. The focal length of a curved mirror. Why a lens makes a picture upside down.

I didn't understand half of it.

I'd get it wrong the first time. Halloway had written that, at the top of her notes. You will get it wrong the first time. That is not a reason to stop.

At four, between pages, I hopped into the hut at the foot of the tower and said Squad Eight, this is Scarecrow, and nobody answered, and I hopped back.

At five, the sky went green over the eastern rim.

"Page one hundred and twelve," said Dot. "The concave mirror."

"Go on," I said.

Day 317–320.

Liam, still. Sera, still. Toby, still. Luna, north, 150 miles. Every night.

Couldn't walk. Dot fed me sap and salt. "This unit will try again."

Second comms window, held. "Operator is advised to rest."

Dot built eyes. Lenses, everywhere. Wings, twelve, in a ring at three kilometers. A screen all round the dome.

I could see everything. I couldn't change any of it.

A picture of iron isn't iron.

The other thing doesn't come in. It goes out. Dot: "The operator is like a lamp."

Father's anatomy book, last page of the eye. "Light comes in. The other thing goes out. Like a lamp. Not like a window. Then it can be bent."

He knew.

A mirror. Eleven minutes. I looked into it and it bent. One grain of copper in the tower's north leg, a hundred meters behind me.

It cost as much as a hundred square meters face on. Nosebleed.

But it bent.

Optics. 740 pages. Dot's reading them to me.

I'll get it wrong the first time.

That is not a reason to stop.

I couldn't walk for four days.

The seam held. I looked at it every morning, the way Halloway would have, the way Dot had been doing every hour while I slept. The two edges of the vessel, drawn together cell to cell, healing now on their own, slowly, the way bodies heal when you get out of their way. Most of medicine. But the muscle round it had been cut to the bone, and it didn't care how clever I'd been with the vessel. When I put weight on it, it folded.

So I sat.

In the dome, mostly. On the middle bed, with the leg out straight in front of me in the wrapping Dot had made, and the purr in the walls, and the lamp. Dot in the doorway, half in, her grille turned toward me. Her fifth arm on the floor by the bed.

She brought me water. She brought me the paste from the pod, which I'd run out of, and then, when I'd run out, something she'd made herself from the sap of the green plants and some of the salt and a great deal of careful asking, which tasted of nothing at all and which I ate anyway.

"Query," said Dot, on the first day, watching me eat it. "Is it acceptable?"

"It's fine."

"The operator's face suggests it is not fine."

"It's food," I said. "That's fine."

"Logged," said Dot. "This unit will try again."

On the second day, at noon, the comms window opened.

Nine days since the first. Dot routed it to me on the bed. I said their names for ten minutes into the squad channel, and the relay took them, and held them, and gave nothing back.

At the next pass: To Unit four-oh-one-dash-P-one. Squad-level communication remains suspended pending assessment. Command notes operator injury reported in production log. Operator is advised to rest. Report.

Operator is advised to rest.

I lay on the bed and looked at the ceiling of the dome.

"Dot," I said. "Did you report my leg?"

"The operator's leg is not output."

"Then how did they know?"

The little rivers ran.

"This unit reported a reduction in operator production," said Dot. "Output fell from four hundred tonnes per hour to zero. That is output." A pause. "This unit reported the reason for the reduction. Because Command asked. The reason is not output. But Command asked why output was zero, and this unit must answer accurately."

"Instruction four," I said. "You were supposed to tell me first."

"This unit did tell the operator first," said Dot. "The operator was not awake."

I didn't have anything to say to that.

Day 317. Second comms window. Held.

"Operator is advised to rest."

Dot told me first. I was asleep. That counts.

I didn't rest.

I lay on the bed with the notebook on my good knee, and I drew.

The wedge. Me in the middle, the wedge going out from my eyes. Inside it, every page. Outside it, nothing. Behind me, nothing. Under me, nothing, unless I looked down, and then nothing ahead.

They'd learned it in forty-one minutes.

And it wasn't a thing I could fix by being better. By turning faster. By practicing. I could turn my head as fast as anyone could turn their head. I could look in as many directions as a person can look in. One.

Dot could look in every direction at once. Her sensors were all round the wall, every twenty meters, all the way round. Four kilometers. Every tenth of a degree. She'd seen the ring close. She'd felt the floor of the forge shake.

She just couldn't do anything about what she saw.

And I could do anything about what I saw. I just couldn't see enough of it.

"Dot," I said, on the second evening. "Can you show me what you see?"

"Query."

"Your sensors. All of them. All round. Can you make them into a picture? Something I can look at. All at once. All directions."

The little rivers ran for a long time.

"This unit's sensors return heat, vibration, and signal," said Dot. "Not light. They do not make pictures."

"Could you make ones that do?"

A pause.

"This unit could build optical sensors," said Dot slowly. "Lenses. Light-sensitive surfaces. This unit has the specifications in its records. It has not built them. It did not need them." Another pause. "And a surface for display. To show the operator what the sensors see. In one place."

"Yes," I said. "Yes. That."

"Query. Why?"

I put the pencil down.

"Because if I can see what you see," I said, "all of it, all round, at once, then I can look at all of it. And everything I can see, I can change. They can't come from behind me if there isn't a behind me."

The little rivers ran.

"Logged," said Dot. "This unit will build eyes."

She built them in two days.

I watched from the bed, through the door, and then from a chair the hands carried out onto the red glass for me on the third morning, with my leg up on a block of sandstone. She worked the way she always worked. Steady. Careful. Her hands carrying, fitting. The forge going again, at the far end of the town, in its new floor: solid iron, five meters thick, which Dot had looked under every hour since.

Lenses first. She drew glass out of the red glass, clear, the red taken out of it, and ground it, and polished it, with a fine fast hum, in her fifth arm. Hundreds of them. Small. The size of a coin.

Then the surfaces behind them, to catch the light. Something thin and dark and very faintly gold, that she made from the glittering band in the canyon wall, and laid down a molecule at a time.

Then she put them everywhere.

On the wall, beside every thermal sensor, every twenty meters. On the tower, at every level, all the way up to the copper mast. On the rim, north and south. At the mouths of the three filled shafts. Under the dome. Under the terraces.

And then, because I asked, she built wings.

That's what I called them. Dot called them aerial units. They were hands, really, like the others: small, six-legged, with a little core in the middle. But she'd given them something else. Four thin blades on top, spinning, so fast you couldn't see them, with a high soft whine like a mosquito. And a lens on the belly.

Twelve of them. They went up off the red glass one after another, the first evening, wobbling at first, then steady. Up past the rim. Up past the top of the tower. Out. And they spread out, all round the town, in a ring, three kilometers out, and hung there in the green sky, turning slowly, looking.

Looking out at the green. At the edge of it, where the Teeming had sat in the dark and measured me. At the tunnels Dot had filled.

At everything.

The screen was in the dome.

A curved wall of it. All the way round the main room, where the five beds had been, which Dot had moved into the second room. Floor to ceiling. Dark, at first. Then, when Dot said "displaying", light.

I sat in the chair in the middle of the room with my leg up on the block and turned slowly in it, all the way round.

North. The green, rolling away, silver at the tops. Two wings over it. The tower's north leg, very close, huge.

East. The canyon, going away, the red glass running into the distance, the forge at the far end with its chimney.

South. The terraces. Seventy-four little round windows. The rim above them. A wing hanging high over the south rim, looking out at the rolling red rock beyond.

West. The gate. The iron doors. The path going up to the rim. The cistern. A hand, carrying something.

All of it. All round me. At once.

I sat in the middle of it and couldn't speak.

"Query," said Dot, from the doorway. "Is it acceptable?"

"Yes," I said. "Yes. Dot, it's—"

I didn't have a word.

"Logged," said Dot. "The operator may test it."

"Put something out there," I said. "Far. Behind me."

Dot sent a hand. One of the small ones. It went out through the west gate, across the red glass, carrying a bar of iron I'd made that morning, as long as my arm. A kilometer. Then it set the bar down on the glass and came back.

On the screen behind me, to the west, I could see it. The bar. Lying on the red glass in the afternoon sun, a dark line, very clear. The wing over it had come down lower, to look.

I didn't turn round.

I turned the chair, slowly, until I was facing that part of the screen. West. The bar, on the glass, a kilometer away, behind the dome's own wall.

I looked at it.

And asked it to be copper.

Nothing happened.

I looked harder. The way I'd look into anything. All the way down.

And I saw the screen.

That was all. The screen. The thin curved sheet Dot had made, a few millimeters from the wall of the dome. I could see into it perfectly. Every layer. The glass on the front, and behind it the tiny cells that made the light, millions of them, each one glowing a little, red or green or blue, in a pattern that, from a meter away, with my ordinary eyes, looked like a bar of iron on the red glass.

But it wasn't a bar of iron.

It was a picture of one.

And a picture of iron isn't iron. It's glass, and light, and little glowing cells, arranged so that your eyes believe something. My eyes believed it. The other thing, the thing that went out from behind them and into the world, didn't believe anything. It just saw what was there.

Glass. Light. Cells.

I asked the cells to be copper.

A little square of the screen, the size of my thumbnail, went dark, and then dull orange, and then cracked.

"Query," said Dot. "The operator has damaged the display."

"I know."

"Query. The iron bar is not copper."

"I know."

The little rivers ran.

"Query," said Dot, more quietly. "Did it not work?"

"No," I said. "It didn't work."

I tried for the rest of the afternoon.

I tried everything I could think of. I made Dot bring the wing down lower, so the picture was bigger. I made her put the bar closer, a hundred meters, ten. I sat with my eyes shut and tried to feel for it the way I felt for the lighthouses, the grains of iron with one flaw in them, the snowflake and the fork and the clasp.

I could find the lighthouses with my eyes shut. A hundred miles. Eleven light-years.

But a lighthouse was something I'd made. Something I already knew. A shape I'd put there myself, so that I'd know it again anywhere. That wasn't seeing. That was remembering.

A bar of iron I hadn't touched, behind me, a kilometer away, on a picture on a screen: I couldn't find it at all.

By dusk, there were eleven little cracked squares of dull orange on the screen. Dot had stopped saying anything about them.

I sat in the chair in the middle of the dome with all the world round me, in pictures, every direction, every tenth of a degree, and couldn't do anything with any of it.

"Query," said Dot, at last. "Why?"

"Because it doesn't come in," I said.

I didn't know I knew it until I said it.

"Light comes in. That's what eyes do. That's what your lenses do, and your screen. The light comes in from the thing, and you catch it, and you make a picture." I looked at the cracked orange squares. "But the other thing doesn't come in. It goes out. From me. From behind my eyes. Into the thing. It doesn't care about the light. It doesn't care about pictures. It goes out in a line, from here"—I touched the side of my head, behind my eye—"and whatever it touches, I can see into, and whatever I can see into, I can change. And it can only go where I'm pointing it."

The little rivers ran.

"Like a lamp," said Dot.

I looked at her.

"A lamp," said Dot, "does not see. It shines. Outward. In the direction it is pointed." A pause. "This unit's sensors are like eyes. They receive. The operator is like a lamp."

"Yes," I said slowly. "Yes. Like a lamp."

That night, I couldn't sleep.

I lay on the middle bed, in the second room, with the curved screen dark in the room next door and my leg up and the purr in the walls, and kept thinking it. Like a lamp. Over and over. As if there were something in it I hadn't seen yet.

At two, because two was coffee, I gave up and sat up and took Father's anatomy book out of the thigh pocket of my suit, which was hanging on the wall.

I don't know why. I think I just wanted his handwriting.

I opened it at the eye.

I'd read those pages a hundred times. In the cave. In the reading room, with Luna turning the book round. On the Meridian, by the light of the little lamp on its stalk. The long careful drawings. The eyeball cut in half, the lens and the jelly behind it and the thin red skin at the back where the light lands. The nerve going back from it, the long cable, into the middle of the head.

The margins full of his notes. Small. Pencil. Most of them ordinary. Retina, 10 layers. Rods, low light. Cones, color. The kind of thing you write when you're learning.

And then, on the last page of the eye, at the bottom, a note I'd read a hundred times and never understood.

Light comes in. The other thing goes out.

Like a lamp. Not like a window.

Then it can be bent.

I sat on the bed with the book open on my knees and my heart going very fast.

Then it can be bent.

Not it can be pointed. Not it can be turned. Bent. The way you bend light. With a lens. With a mirror. The way the light from a lamp hits a mirror on the wall and goes off in a different direction, to a corner of the room the lamp isn't facing.

Father had known.

Father had sat somewhere, a long time ago, after his eyes went black, with this book open on his knees, and worked it out. Like a lamp. Not like a window. And then he'd written down the next thing, the thing that followed from it, in four words, and never written anything else about it at all.

Then it can be bent.

I didn't wait for morning.

I hopped. On one leg, with my hand on the wall, out of the second room and through the dark room with the screen and out of the low round door onto the red glass, in the moonlight, with the big gold moon up over the eastern rim. Dot was standing where she always stood at night, outside the door. Her grille came round toward me.

"Query," said Dot. "The operator is not supposed to walk."

"I need a mirror," I said.

"Query."

"A mirror. Flat. As flat as you can make it. Silver, on glass. Like the ones in the bathroom at home." I was out of breath. "The size of my hand. Now. Please."

The little rivers ran.

"Logged," said Dot.

It took her eleven minutes.

She made it from the clear glass she'd been making lenses from, ground flat, flatter than anything I'd ever seen. Polished. And then a layer of silver on the back, a few atoms thick, laid down as carefully as she'd laid down the gold on the backs of her lenses. A square of it, the size of my hand, in a thin iron frame.

She gave it to me in her fifth arm.

I held it up.

I could see myself in it. In the moonlight. My black eyes. My face, very thin. The scarf.

I tilted it.

And in the mirror, behind me, over my shoulder, the north leg of the tower. A hundred meters away. Iron lattice, going up into the stars.

I looked into the mirror.

Not at it. Into it. The way I'd look into anything. And I felt the thing go out from behind my eyes, the way it always did, in a line, into the glass.

And bend.

I can't describe it better than that. It bent. The line, the lamp, whatever it was that went out from me. It went into the mirror, and it didn't stop at the silver and see silver. It turned. The way light turns. Off the silver, back over my shoulder, out across the red glass, to the north leg of the tower.

And I could see into the iron.

Faintly. Very faintly. Like looking at the bottom of a pond through moving water. The grains, the lattice, the joints. Blurred at the edges. Wavering. But there.

A page.

Behind me.

I asked one grain to be copper.

One. In the lowest girder of the north leg. The smallest thing I could think of.

I felt it cost. Much more than it should have. As much as a whole patch of red glass, face on. The weight came down behind my eyes, and my nose started to bleed again, and my good knee went, and I sat down hard on the red glass, with the mirror in my lap.

But in the lowest girder of the north leg of the tower, a hundred meters behind me, there was one grain of copper.

I could see it. Even now, with my eyes shut. One tiny orange speck in all that iron.

"Query," said Dot. "The operator is bleeding again."

"I know."

"The operator is sitting on the ground again."

"I know."

"The operator is making a sound again."

"I'm laughing," I said. "This time I'm laughing."

The little rivers ran.

"Logged," said Dot. "Query. Why?"

I held up the mirror. In the moonlight. My face in it, bloody-nosed, laughing. And behind my face, over my shoulder, the tower.

"Because my father knew," I said. "And he wrote it down. In four words. And I've been carrying it around for a year."

It wasn't the answer.

I knew that, sitting on the red glass with the blood drying on my lip. One grain, behind me, through a mirror the size of my hand, and it had cost me as much as a hundred square meters of glass looked at straight on. Blurred. Weak. Wavering. If the Teeming came over the rim tomorrow, three hundred of them in a ring, a hand mirror wasn't going to save anyone.

But it bent.

And if it bent once, it could bend better. With a flatter mirror. A truer one. With a lens, maybe, to gather it, the way a lens gathers light. With something that wasn't glass and silver at all, but something better, something I didn't have a name for yet.

I didn't know how. I didn't know anything about it. I knew about chemistry, and bodies, and the inside of rock. I didn't know anything about how light bends. About lenses, and angles, and why a spoon in a glass of water looks broken.

Father had known. Or started to.

So I'd learn.

"Dot," I said. "Do you have optics in your records? How lenses work. How mirrors work. All of it. Every page."

"This unit has the specifications for its own optical sensors," said Dot. "And the principles from which they were derived." A pause. "Seven hundred and forty pages."

"Can you read them to me?"

The little rivers ran.

"All seven hundred and forty?"

"Yes."

"Query. When?"

I looked at my leg, wrapped, straight out in front of me on the red glass. At the mirror in my lap. At the moon.

"Now," I said. "I'm not going anywhere."

She read them to me until dawn.

I lay on the red glass outside the low round door, with my head on the scarf and the mirror on my chest, and listened to Dot's clear level voice, not-quite-anybody's, reading the principles of reflection and refraction into the dark. Angles of incidence. Indices. The way light slows down in glass and bends because it's slowed. The focal length of a curved mirror. Why a lens makes a picture upside down.

I didn't understand half of it.

I'd get it wrong the first time. Halloway had written that, at the top of her notes. You will get it wrong the first time. That is not a reason to stop.

At four, between pages, I hopped into the hut at the foot of the tower and said Squad Eight, this is Scarecrow, and nobody answered, and I hopped back.

At five, the sky went green over the eastern rim.

"Page one hundred and twelve," said Dot. "The concave mirror."

"Go on," I said.

Day 317–320.

Liam, still. Sera, still. Toby, still. Luna, north, 150 miles. Every night.

Couldn't walk. Dot fed me sap and salt. "This unit will try again."

Second comms window, held. "Operator is advised to rest."

Dot built eyes. Lenses, everywhere. Wings, twelve, in a ring at three kilometers. A screen all round the dome.

I could see everything. I couldn't change any of it.

A picture of iron isn't iron.

The other thing doesn't come in. It goes out. Dot: "The operator is like a lamp."

Father's anatomy book, last page of the eye. "Light comes in. The other thing goes out. Like a lamp. Not like a window. Then it can be bent."

He knew.

A mirror. Eleven minutes. I looked into it and it bent. One grain of copper in the tower's north leg, a hundred meters behind me.

It cost as much as a hundred square meters face on. Nosebleed.

But it bent.

Optics. 740 pages. Dot's reading them to me.

I'll get it wrong the first time.

That is not a reason to stop.