It would be fun to fence with people I’ve never seen before. People whose patterns I do not know. People who are normal and will not know that I am not normal. Or will Tom tell them? Somehow I do not think he will.

Next Saturday I am going to the planetarium with Eric and Linda. The following Saturday, it is the third of the month, and I always spend extra time cleaning my apartment on the third Saturday of the month. The tournament is the Saturday after. I do not have anything planned for then.

When I get home I pencil in “fencing tournament” on the fourth Saturday of the month. I think about calling Tom, but it is late and, besides, he said to tell him next week. I put a reminder sticky on the calendar: “Tell Tom yes.”

By Friday afternoon Mr. Crenshaw has still not said anything to us about the experimental treatment. Maybe Mr. Aldrin was wrong. Maybe Mr. Aldrin talked him out of it. On-line, there’s a flurry of discussion, mostly on the private news groups, but nobody seems to know when or where human trials are scheduled.

I do not say anything on-line about what Mr. Aldrin told us. He did not say not to talk about it, but it does not feel right. If Mr. Crenshaw has changed his mind and everyone gets upset, then he will be angry. He looks angry much of the time anyway when he comes to check on us.

The show at the planetarium is “Exploring the Outer Planets and Their Satellites.” It has been on since Labor Day, which means it is not too crowded now, even on Saturday. I go early, to the first showing, which is also less crowded even on days when it is crowded. Only a third of the seats are occupied, so Eric and Linda and I can take up a whole row without being too close to anyone.

The amphitheater smells funny, but it always does. As the lights dim and the artificial sky darkens, I feel the same old excitement. Even though these pinpricks of light that begin to show on the dome are not really stars, it is about stars. The light is not as old; it has not been worn smooth by its passage through billions and billions of miles — it has come from a projector less than a ten-thousandth of a light-second away — but I still enjoy it.

What I don’t enjoy is the long introduction that talks about what we knew a hundred years ago, and fifty years ago, and so on. I want to know what we know now, not what my parents might have heard when they were children. What difference does it make if someone in the distant past thought there were canals on Mars?

The plush on my seat has a hard, rough spot. I feel it with my fingers — someone has stuck gum or candy there and the cleaning compound hasn’t taken it all. Once I notice it, I can’t not notice it. I slide my brochure between me and the rough spot.

Finally the program moves out of history and into the present. The latest space-probe photographs of the outer planets are spectacular; the simulated flybys almost make me feel that I could fall out of my seat into the gravity well of one planet after another. I wish I could be there myself. When I was little and first saw newscasts of people in space I wanted to be an astronaut, but I know that’s impossible. Even if I had the new LifeTime treatment so I would live long enough, I would still be autistic. What you can’t change don’t grieve over, my mother said.

I don’t learn anything I don’t already know, but I enjoy the show anyway. After the show, I am hungry. It is past my usual lunchtime.

“We could have lunch,” Eric says.

“I am going home,” I say. I have good jerky at home, and apples that will not be crisp much longer.

Eric nods and turns away.

On Sunday I go to church. The organist plays Mozart before the service starts. The music sounds right with the formality of the worship. It all matches, like shirt and tie and jacket should match: not alike but fitting together harmoniously. The choir sings a pleasant anthem by Rutter. I do not like Rutter as much as Mozart, but it doesn’t make my head hurt.

Monday is cooler, with a damp chill breeze out of the northeast. It is not cold enough to wear a jacket or sweater, but it is more comfortable. I know that the worst of the summer is over.

On Tuesday it is warm again. Tuesdays I do my grocery shopping. The stores are less crowded on Tuesdays, even when Tuesday falls on the first of the month.

I watch the people in the grocery store. When I was a child, we were told that soon there would be no grocery stores. Everyone would order their food over the Internet, and it would be delivered to their doors. The family next door did that for a while, and my mother thought it was silly. She and Mrs. Taylor used to argue about it. Their faces would get shiny, and their voices sounded like knives scraping together. I thought they hated each other when I was little, before I learned that grownups — people — could disagree and argue without disliking each other.

There are still places where you can have your groceries delivered, but around here the places that tried it went out of business. What you can do now is order groceries to be held in the “Quick Pickup” section, where a conveyor belt delivers a box to the pickup lane. I do that sometimes, but not often. It costs 10 percent more, and it is important for me to have the experience of shopping. That’s what my mother said. Mrs. Taylor said maybe I was getting enough stress without that, but my mother said Mrs. Taylor was too sensitive. Sometimes I wished that Mrs. Taylor was my mother instead of my mother, but then I felt bad about that, too.

When people in the grocery store are shopping alone, they often look worried and intent and they ignore others. Mother taught me about the social etiquette of grocery stores, and a lot of it came easily to me, despite the noise and confusion. Because no one expects to stop and chat with strangers, they avoid eye contact, making it easy to watch them covertly without annoying them. They don’t mind that I don’t make eye contact, though it is polite to look directly at the person who takes your card or money, just for a moment. It is polite to say something about the weather, even if the person in front of you in line said almost the same thing, but you don’t have to.

Sometimes I wonder how normal normal people are, and I wonder that most in the grocery store. In our Daily Life Skills classes, we were taught to make a list and go directly from one aisle to another, checking off items on the list. Our teacher advised us to research prices ahead of time, in the newspaper, rather than compare prices while standing in the aisle. I thought — he told us — that he was teaching us how normal people shop.

But the man who is blocking the aisle in front of me has not had that lecture. He seems normal, but he is looking at every single jar of spaghetti sauce, comparing prices, reading labels. Beyond him, a short gray-haired woman with thick glasses is trying to peer past him at the same shelves; I think she wants one of the sauces on my side, but he is in the way and she is not willing to bother him. Neither am I. The muscles of his face are tight, making little bulges on his brow and cheeks and chin. His skin is a little shiny. He is angry. The gray-haired woman and I both know that a well-dressed man who looks angry can explode if he is bothered.

Suddenly he looks up and catches my eye. His face flushes and looks redder and shinier. “You could have said something!” he says, yanking his basket to one side, blocking the gray-haired woman even more. I smile at her and nod; she pushes her basket out around him, and then I go through.

“It’s so stupid,” I hear him mutter. “Why can’t they all be the same size?”

I know better than to answer him, though it is tempting. If people talk, they expect someone to listen. I am supposed to pay attention and listen when people talk, and I have trained myself to do that most of the time. In a grocery store sometimes people do not expect an answer and they get angry if you answer them. This man is already angry. I can feel my heart beating.