1. A round city gets a square drawn around the circle
2. A city that is wider on one side than the other will be “boxed off” – the two sides are considered of equal length, adding to the narrow side to form a square
3. If there are dwelling places at the edge of the city, the lines will be drawn so that those houses are included
4. If the city is shaped like a bow or like the Greek letter Gamma, we view the empty space as though it were filled with houses.
Regarding the last case, Rav Huna comments that the ruling will be different if the empty area between the two ends of the city is larger than 4,000 amot.
If there are less than four thousand cubits between the two ends of the bow, so that the Shabbat limits measured from the two ends of the city overlap, the interior space of the bow is regarded as if it were filled with houses, and one measures the Shabbat limit of the city from the imaginary bowstring stretched between the two ends of the bow. But if that is not the case, and the distance between the two ends of the bow is four thousand cubits or more, one measures the Shabbat limit from the bow itself.
The question raised by the rishonim about Rav Huna’s ruling is that we learned in the Mishna that dwelling places extending beyond the normal city lines will cause the tehum (=boundary) to be extended, so that they should be included. Shouldn’t that rule apply to the case of the bow-shaped city, as well?
The Ra’avad accepts this argument and rules that even in the case of the Mishna we will not extend the boundaries of the city if the dwelling places beyond the city are not within 4,000 amot of one-another. The Rashba explains that the extra dwelling places will naturally be spread out throughout the city and its environs, while the city shaped like a bow, will, by definition, continue to develop in that shape and direction.