Shabbos, Chapter 11, Mishnah 3. This mishnah deals with two matters: one who throws an object four cubits against a wall, and an object that was thrown and then rolled away from the place where it was presumed to have come to rest.
"Hazoreik arba amos b'kosel":
This refers to a person who throws an object four cubits in a public domain against a wall, and the object sticks to the wall - such as a piece of fruit or something else that adheres. The ruling depends on the height that the object reached:
"L'ma'alah mei'asarah tefachim - k'zoreik ba'avir" - if the object stuck above ten handbreadths, it is as though he threw it into the air, since above ten handbreadths is not considered a public domain but rather an exempt area. Therefore the thrower is not liable, because the throwing was not done within the public domain.
"L'matah mei'asarah tefachim - k'zoreik ba'aretz" - if the object stuck below ten handbreadths, it is as though he threw it onto the ground or close to it, and he is liable for throwing an object four cubits in a public domain.
The Gemara makes a precise inference and teaches that even when the distance from the place of throwing upward to the wall is exactly four cubits, we do not say that the thickness of the fruit itself reduces the measure of four cubits; rather, we measure the distance that the object traveled upward along the wall, and that is a full four cubits.
"Zarak l'soch arba amos v'nisgalgel chutz l'arba amos":
A person who threw an object intending that it come to rest within four cubits, and the object rolled and came to rest beyond four cubits, is exempt. Two explanations are given for this:
Even though in the end the object came to rest beyond four cubits, his intention was that it come to rest within four cubits, and for that reason he is exempt.
Some explain that the object came to rest for a brief moment within the four cubits before it continued and rolled beyond them, and therefore he is exempt, since the initial resting was within four cubits.
"Chutz l'arba amos v'nisgalgel l'soch arba amos":
However, if a person threw an object beyond four cubits, and the object rolled and entered within the four cubits, he is liable. Here too there are two ways of explaining this:
The Gemara explains that this refers to an object that came to rest for a brief moment beyond the four cubits before it rolled inward, and for that reason he is liable.
Others explain that even if the object did not come to rest at all, it is enough that it lingered in the air for some time past four cubits to render him liable, even though in the end it arrived within the four cubits.
In summary: In this mishnah we learned that when one throws against a wall, everything depends on the height: above ten handbreadths is an exempt area, while below ten handbreadths it is like throwing onto the ground and he is liable, and the thickness of the object does not reduce the measure of four cubits. We also learned that when an object rolls, we follow the initial resting: if he threw it within four cubits and it rolled out, he is exempt, and if he threw it beyond four cubits and it rolled in, he is liable.