Let's say a person's in the sun. Yesterday, Baruch Hashem, was a beautiful day, so he's sitting in the backyard. We had a Shabbat, and it's very, very sunny. He says, "You know what? I have a good idea. Let me go take two chairs, and I'll take a blanket and I'll put it over the two chairs just to protect me from the sun." Is a person allowed to do that? It's temporary. Rabotai (gentlemen), the Halacha (Jewish law) is no.
Why? It's called Ohel Arai. Meaning, it's a tent. And a tent is a Toledah, meaning it's a subset of Boneh (building), and therefore present now. The rabbi is right. Really, the problem is a permanent tent. Why? Because that's really Boneh. Okay, so we're scared that if you do that, you're going to come to really erect a real edifice. So the rabbi is right. So we don't want you to do a temporary ohel because you might come to do a permanent ohel. Therefore, putting something over you, a roof, is Assur (forbidden). A person is not allowed to do that.
What about a mechitza (partition)? Can I put up a wall if I want to? Like, you know, a temporary wall. It's like, you know, a curtain on the wall. I do that. That we'll discuss in the future, because it also affects things like strollers. We'll talk about it in a bit, Hashem. Have a wonderful day.