Quickly review רמב”ם ה’ שבת פרק טז הלכה טז
https://hebrewbooks.org/pdfpager.aspx?req=14278&st=&pgnum=70
We asked the two following questions on the Rambam
1. The Rambam concludes that each situation individually a צורת הפתח is valid. However when both are combined in a case of an opening wider than 10 Amos and פרוץ מרובה על העומד than it is disqualified.
If each situation independently is valid, why is the combination deadly?
2. Our Gemara said the source to disqualify a צורת הפתח when there are more openings than closures – פרוץ מרובה על העומד is from the halacha of Rav who rules a צורת הפתח can not close an opening wider than 10 Amos. Since the Rambam concludes a צורת הפתח is valid on an opening wider than 10 Amos where is the source to disqualify it when there is פרוץ מרובה על העומד ?
Learn מגיד משנה for an answer
Learn ר’ חיים על הרמב”ם שבת טז, טז who gives fundamental principles in Hilchos Mechitzas
https://hebrewbooks.org/pdfpager.aspx?req=61915&st=&pgnum=39&hilite=
Breakdown the ר’ חיים to segments
1. The two aspects of a צורת הפתח
2. How a צורת הפתח on an opening is better than without one even when the opening is less than 10 Amos
3. The bearing עומד מרובה has to the opening in the mechitza.
4. The difference between a solid mechitza and a צורת הפתח which acts as a mechitza.