If he throws it less than four cubits, he is exempt, as he is neither liable for carrying from domain to domain nor for carrying in the public domain. The Gemara asks: What is he teaching us with this halakha? The Gemara answers: He is teaching us the following two things. First, that domains join together; even though one public domain is separated from the other by a private domain, they are treated as one domain. And second, that we do not say that an object in airspace is considered at rest. The object is not considered to have landed in a private domain, and therefore the one who threw it is exempt.

Rav Shmuel bar Yehuda said that Rav Abba said that Rav Huna said that Rav said: One who carries an object four cubits in the covered public domain is exempt because it is not similar to the flags of the camp of Israel in the desert, which were not covered. The Gemara wonders: Is that so? Weren’t the wagons on which they transported the beams of the Tabernacle covered? The beams formed a covering over the wagons. And even so, Rav said in the name of Rabbi Ḥiyya: The areas that were beneath the wagons, and between them, and on their sides are all considered to have been the public domain. Apparently, even a covered public domain, like the space beneath the wagons, has the legal status of a public domain. The Gemara answers: When Rav said that the space beneath the wagons had the legal status of a public domain, he was referring to when the beams were arranged in stacks. The beams did not cover the entire area of the wagon. There was space between the stacks.

The Gemara asks: After all, how much was the length of a wagon? It was five cubits. How much was the width of a beam? It was a cubit and a half. How many beams could one place on a wagon? One could place three stacks of beams, totaling four and a half cubits. If so, half a cubit of open space remained. When the Master distributes half a cubit between the stacks of beams it is considered lavud, attached, as the space between each stack was less than three handbreadths. The Gemara answers: Do you maintain that they would place the beams on their width? They would place them on their depth, which was one cubit wide, and therefore there was a greater distance between the rows.

The Gemara asks: Ultimately, how much was the depth of a beam? It was one cubit. How many stacks would they place? They would place four stacks. One cubit of open space remained. When the Master distributes one cubit between the four stacks of beams it is considered lavud, as two handbreadths separated each stack. The Gemara adds: This statement of Rav works out well according to the opinion of the one who said that the beams in the Tabernacle were one cubit thick at the bottom, and they narrowed to a fingerbreadth as they reached the top. According to that opinion, there was a space larger than three handbreadths at least between the tops of the beams, and therefore the area beneath that part of the wagon was not covered. However, according to the opinion of the one who said that just as they were one cubit thick at the bottom, so too, the beams were one cubit thick on top, what can be said? In that case, the space between the stacks was less than three handbreadths, and area beneath the wagon had the legal status of a covered public domain.

Rav Kahana said: When we said that the underside of the wagon was considered to be a public domain, the statement was not referring to when the beams were stacked on them. When the wagon was empty and consisted of the frames that held the beams in place, beneath the wagon was an uncovered public domain. The Gemara asks: But where would they place the frames? On top of the wagon when the beams were already stacked on it and the wagon itself was already covered by the beams, as stated above (ge’onim).