Eiruvin 2:1-2

Eiruvin 2:1

If a well is in the public domain, Rabbi Yehuda says boards may be set up at right angles at each corner to permit drawing water. (The mishna calls this “four that look like eight.”) Rabbi Meir requires an additional board on each side between the corner pieces (“eight that look like 12”). The height of these boards must be at least ten handbreadths (about 30”), their width six handbreadths (about 18”), and their thickness may be anything. The maximum space between the boards may be enough for two teams of three oxen each according to Rabbi Meir. Rabbi Yehuda says the space may be enough for two teams of four oxen each, tied close together, with one team entering the enclosure and the other exiting. (The Talmud clarifies that Rabbi Meir’s opinion is ten cubits – about 15 feet – while Rabbi Yehuda’s opinion is 13.3 cubits – more like 20 feet.)

Eiruvin 2:2

The boards enclosing a well may be placed close to it so long as there’s enough room for a cow’s head and the greater part of its body to fit while it drinks. The boards may be placed as far away from the well as one likes as long as one keeps increasing the number of boards to ensure that there’s never more than the maximum amount of space in between boards (10 cubits according to Rabbi Meir, 13.3 cubits according to Rabbi Yehuda).