Yosef Karo, Translation:Shulchan Aruch — Orach Chaim 364…
“ Paragraph 5 - If an alley is shaped like a centipede, meaning that it is a big alley with many small alleys open to it, and the secondary alleys are open to the public domain, even if the small openings are not opposite each other, each one needs the frame of an entrance at its opening to the big alley. In the other side where it is open to the public domain, it needs a stake or a beam. If the big alley is open on both sides, one side needs the frame of an entrance and the other side needs a stake or beam. If it is open on one side, it needs a beam or stake at its opening. ”
