Hilchot Shabbat - פרק ט״ז (ב)

<p><strong>Perek ט״ז (ב): What Makes a Wall a Wall?</strong><br>This second half of this Perek finishes the case of the Shayara. The Rambam then turns to the Mechitza itself, the wall that creates a Halachic boundary. What must it withstand? How tall must it be? How many gaps can it have before it stops counting, and what is the difference between a breach and a doorway-shaped opening (Tzurat Petach)? We look at walls made of reeds and ropes, and even of people and animals. The Perek closes with the question of a wall that appears on Shabbat itself, and the shade of a low-hanging tree.</p>