Halachot Purim #2: Rambam Hilchot Megillah Chapter 1-Chapter 2 - Seeing a Walled City, Lines in a Megillah - Feb 24, 2021 - Rambam Hilchot Megillah end of Perek 1 through beginning of Perek 2.

Defining the Rambam when he write: וְכָל הַנִּרְאֶה עִמּוֹ - When do people who see Yerushalayim keep Purim?

City of Ramot (Near Jerusalem) Yabia Omer (Chelek 7 OC Siman 58), Rav Masas (Shemesh Umagen OC Siman 55),

How many lines should be on your megillah? Shulchan Aruch (Siman 691 Saif 4) - וצריך לכתוב איש בראש דפא ואת בסופה, Gra (Maase Rav Siman 243) 11 lines