Very quickly review גמרא דף יא: “גופא (tenth wide line) until “אשכחיה רב ששת ” (seven lines before the next Mishnah)
Review
שולחן ארוך או”ח ס’ שס”ב סעיף יא
https://hebrewbooks.org/pdfpager.aspx?req=60389&st=&pgnum=54
Learn משנה ברורה ס”ק סו which discusses a machlokes whether the top crossbeam/ string needs to be taught so it will not sway in the wind.
https://hebrewbooks.org/pdfpager.aspx?req=60389&st=&pgnum=55
What is the issue of the top string swaying in the wind?
How much swaying is acceptable?
The Mishna Berurah brings the opinion of the מחצית השקל that is based on a phenomenal chidush in what creates the mechitza of a צורת הפתח
Learn the חזון איש או”ח ס’ ע”ז ס”ק ו (in the back of some prints of the Mishna Berurah) who
https://hebrewbooks.org/pdfpager.aspx?req=14336&st=&pgnum=238
1. Disagrees on the מחצית השקל opinion of what creates the mechitza from a צורת הפתח
2. Explains the issue of swaying in the wind
3. Gives an amount of how much swaying will disqualify
Other opinions on amount of swaying in the wind.
See ערוך השולחן או”ח ס’ שס”ב סע’ לז
https://hebrewbooks.org/pdfpager.aspx?req=9101&st=&pgnum=429
See אג”מ או”ח ח”ה ס’ מ אות ב (in middle)
https://hebrewbooks.org/pdfpager.aspx?req=922&st=&pgnum=176
See אמרי יושר ח”ב ס’ קל”ג
https://hebrewbooks.org/pdfpager.aspx?req=609&st=&pgnum=397&hilite=