Light? Could that really be what light was like?

It occurred once more, another—

The words came to her, words she’d read a thousand times before, words that she’d had no idea — now, she understood, as she … God, as she saw for the first time — words that she’d had no conception of what they’d really meant: flashes of light, bursts of light, flickering lights, and—

She staggered some more, found her chair, collapsed into it, the chair rolling on its casters a bit as her weight hit it.

The light wasn’t uniform. At first she’d thought it was sometimes bright — its intensity greater, a concept she knew from sound — and sometimes dim. But there was more to it than that. For the light she was seeing now wasn’t just dimmer, it was also—

There was nothing else it could be, was there?

She was breathing rapidly, doubly grateful now for the cool air coming in from outside.

The light didn’t just vary in brightness but also—

Good God!

But also in color. That had to be it: these different … flavors of light, they were colors!

She thought about calling out to her mother, her father, but she didn’t want to do anything that might break the moment, the spell, the magic.

She had no idea which colors she was seeing. Oh, she knew names from her reading, but what they corresponded to she hadn’t a clue. But the flashing light she’d just seen was … was darker, somehow, and not just in intensity, than the lights of a moments ago. And—

Jesus! And now there were a few more lights, and they were … were persisting, not flickering, but staying … staying illuminated — that was the word. And it wasn’t just a formless light but rather a light with extent, a…

Yes, yes! She’d known intellectually what lines were but she’d never visualized one before. But that’s what it had to be: a line, a straight beam of light, and—

And now there were two other beams, crisscrossing it, and their colors—

A word came to her that seemed applicable: the colors contrasted with each other, clashed even.

Colors. And lines. Lines defining — shapes!

Again, concepts she knew but had never visualized: perpendicular lines, parallel lines that — God! — converged at infinity.

Her heart was going to burst. She was seeing!

But what was she seeing? Lines. Colors. Shapes, at least as created by intersecting lines, although she still didn’t know what shapes. She’d read about this in preparation for receiving Kuroda’s equipment: people gaining sight knew what squares and triangles were conceptually, and by touch, but didn’t initially recognize them when they actually saw them.

She was still in the padded chair and, despite all the visual disorientation, had no trouble swinging it to face the window. Her perspective shifted, and she could feel the breeze on her face again, and smell that one of her neighbors was using a fireplace. She knew that the window frame was rectangular, knew that it was divided into a lower and upper square by a crosspiece. Surely she would recognize those simple shapes as she looked at them, and—

But no. No. What she was seeing now was a — what words to use? — a radial pattern, three lines of different colors converging on a single point.

She got up from the chair, moved to the window, and stood before it, grasping one side of the frame in each hand. And then she stared ahead, forcing her concentration onto what must be in front of her. She knew she should be seeing lines perpendicular to the floor and others parallel to it. She knew the frame was twice as tall as the crosspiece.

But what she saw bore no relationship — none! — to what she expected. Instead of anything that resembled the window frame, she was still seeing the radial lines stretching away, and—

Strange. When she moved her head, the view did change, as if she were now looking somewhere else. The center point of all the intersecting lines was now off to one side, and — oh, my! — another such grouping was coming into view on the other side, but the lines didn’t seem to correspond to anything in her bedroom.

But wait! It was night now. Yes, the room lights had doubtless been on when her father had been here, but he was serious about saving electricity, forever complaining that Caitlin’s mom had left lights on in the kitchen or bathroom — something, fortunately, she never had to worry about being blamed for. He surely would have turned the lights off when he left. (Bashira had said it was creepy that Caitlin’s dad did that, but, really, it was sensible … wasn’t it?) She couldn’t remember hearing the tiny sound of the switch when he left, but he must have used it — and so the room must be dark now, and what she was seeing were just (again a concept she had never experienced) shadows, or something like that.

She turned, her strange view wheeling as she did so. It was disconcerting and disorienting; she’d crossed this room hundreds of times, but she was having trouble walking because of the distraction. Still, the room wasn’t that big, and it took only seconds to find the light switch. It was pointing down, but she wasn’t sure if that was the position for on or off. She moved it up, and—

Nothing. No change. No new flash of light — nor any dimming of what she was already seeing.

And then she was hit by a thought that should have already occurred to her. Vision was supposed to be at the user’s discretion; surely she could shut all this out just by closing her eyes, and—

And nothing.

No difference. The lights, the lines, the colors were all still there. Her heart fell. Whatever she was seeing had no relation to external reality; no wonder she hadn’t been able to recognize the window frame. She opened and closed her eyes a couple more times, just to be sure, and flicked the room light on and off (or perhaps off and on!) a few more times, as well.

Caitlin slowly made her way back to her bed and sat on its edge. She’d felt momentarily dizzy as she crossed the room, distracted by the lights, and she lay down, her face pointing up at the ceiling she’d never seen.

She tried to make sense of what she was seeing. If she held her head still, the same part of the image did stay in the … the center. And there was a limit to what she could see — things off to the sides were out of her … her … field of view, that was it. Clearly this bizarre show of lights was behaving like vision, behaving as though it were controlled by her eyes, even if the images she was experiencing didn’t have anything to do with what those eyes should be seeing.

Some lines seemed to persist: there was a big one of a darkish color she decided to provisionally call “red,” although it almost certainly wasn’t that. And another — might as well call it “green” — crossed it near the center of her vision. Those lines seemed to stay put overhead; whenever she directed her eyes toward the ceiling, they were there.

She’d read about people’s vision adapting to darkness, so that stars (how she would love to see stars!) slowly became more visible. And although she still didn’t know if she was in the dark or in a brightly lit room, as time passed she did seem to be seeing increasing amounts of detail — a finer and more complex filigree of crisscrossing colored lines. But what was causing it? And what did it represent?

She was unused to … what was it now? That phrase she’d read on those websites about vision Kuroda had directed her to, the phrase that was so musical? She frowned, and it came to her: confabulation across saccades. Human eyes swing in continuous arcs when switching from looking at point A to point B, but the brain shuts off the input, perhaps to avoid dizziness, while the eyes are repositioning. Instead of getting swish pans — a term she’d encountered in an article about filmmaking — vision is a series of jump cuts: instantaneous changes from looking at this to looking at that, with the movement of the eye edited out of the conscious experience. The eye normally made several saccades each second: rapid, jerky movements.