I've come across facemasks that are 4 corned, therefore would it require tzitzit or as its for health reasons exclude this commandment.

In a previous discussion, it was stated: The Maggid Mishnah in Hilchos Shabbos (17:26) says that one may rely on π=3, but he says in Hilchos Eiruvin (3:2) that one may not rely on √2=1.4. I can't actually find the Maggid Mishnah saying either of these things in the passages cited. I'm sure this...